diff --git a/sqlbuilder/bool_expression_test.go b/sqlbuilder/bool_expression_test.go
index c86ba21..de5e2bc 100644
--- a/sqlbuilder/bool_expression_test.go
+++ b/sqlbuilder/bool_expression_test.go
@@ -1,8 +1,6 @@
 package sqlbuilder
 
 import (
-	"fmt"
-	"gotest.tools/assert"
 	"testing"
 )
 
@@ -18,6 +16,10 @@ func TestBoolExpressionNOT_EQ(t *testing.T) {
 
 func TestBoolExpressionIS_TRUE(t *testing.T) {
 	assertExpressionSerialize(t, table1ColBool.IS_TRUE(), "table1.colBool IS TRUE")
+	assertExpressionSerialize(t, (Int(2).EQ(table1ColInt)).IS_TRUE(),
+		`($1 = table1.colInt) IS TRUE`, int64(2))
+	assertExpressionSerialize(t, (Int(2).EQ(table1ColInt)).IS_TRUE().AND(Int(4).EQ(table2ColInt)),
+		`(($1 = table1.colInt) IS TRUE AND ($2 = table2.colInt))`, int64(2), int64(4))
 }
 
 func TestBoolExpressionIS_NOT_TRUE(t *testing.T) {
@@ -40,155 +42,32 @@ func TestBoolExpressionIS_NOT_UNKNOWN(t *testing.T) {
 	assertExpressionSerialize(t, table1ColBool.IS_NOT_UNKNOWN(), "table1.colBool IS NOT UNKNOWN")
 }
 
-func TestBinaryExpression(t *testing.T) {
-	boolExpression := EQ(Literal(2), Literal(3))
+func TestBinaryBoolExpression(t *testing.T) {
+	boolExpression := Int(2).EQ(Int(3))
 
-	out := queryData{}
-	err := boolExpression.serialize(select_statement, &out)
-
-	assert.NilError(t, err)
-
-	assert.Equal(t, out.buff.String(), "($1 = $2)")
-	assert.Equal(t, len(out.args), 2)
-
-	t.Run("alias", func(t *testing.T) {
-		alias := boolExpression.AS("alias_eq_expression")
-
-		out := queryData{}
-		err := alias.serializeForProjection(select_statement, &out)
-
-		assert.NilError(t, err)
-		assert.Equal(t, out.buff.String(), `$1 = $2 AS "alias_eq_expression"`)
-	})
-
-	t.Run("and", func(t *testing.T) {
-		exp := boolExpression.AND(EQ(Literal(4), Literal(5)))
-
-		out := queryData{}
-		err := exp.serialize(select_statement, &out)
-
-		assert.NilError(t, err)
-		assert.Equal(t, out.buff.String(), `(($1 = $2) AND ($3 = $4))`)
-	})
-
-	t.Run("or", func(t *testing.T) {
-		exp := boolExpression.OR(EQ(Literal(4), Literal(5)))
-
-		out := queryData{}
-		err := exp.serialize(select_statement, &out)
-
-		assert.NilError(t, err)
-		assert.Equal(t, out.buff.String(), `(($1 = $2) OR ($3 = $4))`)
-	})
+	assertExpressionSerialize(t, boolExpression, "($1 = $2)", int64(2), int64(3))
+	assertProjectionSerialize(t, boolExpression.AS("alias_eq_expression"),
+		`$1 = $2 AS "alias_eq_expression"`, int64(2), int64(3))
+	assertExpressionSerialize(t, boolExpression.AND(Int(4).EQ(Int(5))),
+		"(($1 = $2) AND ($3 = $4))", int64(2), int64(3), int64(4), int64(5))
+	assertExpressionSerialize(t, boolExpression.OR(Int(4).EQ(Int(5))),
+		"(($1 = $2) OR ($3 = $4))", int64(2), int64(3), int64(4), int64(5))
 }
-
-func TestUnaryExpression(t *testing.T) {
-	notExpression := NOT(EQ(Literal(2), Literal(1)))
-
-	out := queryData{}
-	err := notExpression.serialize(select_statement, &out)
-
-	assert.NilError(t, err)
-	assert.Equal(t, out.buff.String(), "NOT ($1 = $2)")
-
-	t.Run("alias", func(t *testing.T) {
-		alias := notExpression.AS("alias_not_expression")
-
-		out := queryData{}
-		err := alias.serializeForProjection(select_statement, &out)
-
-		assert.NilError(t, err)
-		assert.Equal(t, out.buff.String(), `NOT ($1 = $2) AS "alias_not_expression"`)
-	})
-
-	t.Run("and", func(t *testing.T) {
-		exp := notExpression.AND(EQ(Literal(4), Literal(5)))
-
-		out := queryData{}
-		err := exp.serialize(select_statement, &out)
-
-		assert.NilError(t, err)
-		assert.Equal(t, out.buff.String(), `(NOT ($1 = $2) AND ($3 = $4))`)
-	})
-}
-
-func TestUnaryIsTrueExpression(t *testing.T) {
-	exp := IS_TRUE(EQ(Literal(2), Literal(1)))
-
-	out := queryData{}
-	err := exp.serialize(select_statement, &out)
-
-	assert.NilError(t, err)
-	assert.Equal(t, out.buff.String(), "($1 = $2) IS TRUE")
-
-	t.Run("and", func(t *testing.T) {
-		exp := exp.AND(EQ(Literal(4), Literal(5)))
-
-		out := queryData{}
-		err := exp.serialize(select_statement, &out)
-
-		assert.NilError(t, err)
-		assert.Equal(t, out.buff.String(), `(($1 = $2) IS TRUE AND ($3 = $4))`)
-	})
-}
-
 func TestBoolLiteral(t *testing.T) {
-	literal := Bool(true)
-
-	out := queryData{}
-	err := literal.serialize(select_statement, &out)
-
-	assert.NilError(t, err)
-
-	assert.Equal(t, out.buff.String(), "$1")
+	assertExpressionSerialize(t, Bool(true), "$1", true)
+	assertExpressionSerialize(t, Bool(false), "$1", false)
 }
 
 func TestExists(t *testing.T) {
-	query := EXISTS(
+
+	assertExpressionSerialize(t, EXISTS(
 		table2.
-			SELECT(Literal(1)).
+			SELECT(Int(1)).
 			WHERE(table1Col1.EQ(table2Col3)),
-	)
-
-	out := queryData{}
-	err := query.serialize(select_statement, &out)
-
-	fmt.Println(out.buff.String())
-
-	assert.NilError(t, err)
-
-	expectedSql :=
+	),
 		`EXISTS (
      SELECT $1
      FROM db.table2
      WHERE table1.col1 = table2.col3
-)`
-	assert.Equal(t, out.buff.String(), expectedSql)
-}
-
-func TestIn(t *testing.T) {
-	query := Literal(1.11).IN(table1.SELECT(table1Col1))
-
-	out := queryData{}
-	err := query.serialize(select_statement, &out, NO_WRAP)
-
-	assert.NilError(t, err)
-	fmt.Println(out.buff.String())
-	assert.Equal(t, out.buff.String(), `$1 IN (
-     SELECT table1.col1 AS "table1.col1"
-     FROM db.table1
-)`)
-
-	query2 := ROW(Literal(12), table1Col1).IN(table2.SELECT(table2Col3, table3Col1))
-
-	out = queryData{}
-	err = query2.serialize(select_statement, &out)
-
-	assert.NilError(t, err)
-	fmt.Println(out.buff.String())
-	assert.Equal(t, out.buff.String(), `(ROW($1, table1.col1) IN (
-     SELECT table2.col3 AS "table2.col3",
-          table3.col1 AS "table3.col1"
-     FROM db.table2
-))`)
+)`, int64(1))
 }
diff --git a/sqlbuilder/delete_statement_test.go b/sqlbuilder/delete_statement_test.go
index a81aa9f..ebaff1a 100644
--- a/sqlbuilder/delete_statement_test.go
+++ b/sqlbuilder/delete_statement_test.go
@@ -1,7 +1,6 @@
 package sqlbuilder
 
 import (
-	"fmt"
 	"gotest.tools/assert"
 	"testing"
 )
@@ -15,7 +14,6 @@ func TestDeleteWithWhere(t *testing.T) {
 	sql, _, err := table1.DELETE().WHERE(table1Col1.EQ(Int(1))).Sql()
 	assert.NilError(t, err)
 
-	fmt.Println(sql)
 	expectedSql := `
 DELETE FROM db.table1
 WHERE table1.col1 = $1;
diff --git a/sqlbuilder/expression.go b/sqlbuilder/expression.go
index 00b0d00..1f4f3bc 100644
--- a/sqlbuilder/expression.go
+++ b/sqlbuilder/expression.go
@@ -14,8 +14,8 @@ type expression interface {
 	IS_NULL() BoolExpression
 	IS_NOT_NULL() BoolExpression
 
-	IN(subQuery selectStatement) BoolExpression
-	NOT_IN(subQuery selectStatement) BoolExpression
+	IN(expressions ...expression) BoolExpression
+	NOT_IN(expressions ...expression) BoolExpression
 
 	AS(alias string) projection
 
@@ -46,12 +46,12 @@ func (e *expressionInterfaceImpl) IS_NOT_NULL() BoolExpression {
 	return newPostifxBoolExpression(e.parent, "IS NOT NULL")
 }
 
-func (e *expressionInterfaceImpl) IN(subQuery selectStatement) BoolExpression {
-	return newBinaryBoolExpression(e.parent, subQuery, "IN")
+func (e *expressionInterfaceImpl) IN(expressions ...expression) BoolExpression {
+	return newBinaryBoolExpression(e.parent, WRAP(expressions...), "IN")
 }
 
-func (e *expressionInterfaceImpl) NOT_IN(subQuery selectStatement) BoolExpression {
-	return newBinaryBoolExpression(e.parent, subQuery, "NOT IN")
+func (e *expressionInterfaceImpl) NOT_IN(expressions ...expression) BoolExpression {
+	return newBinaryBoolExpression(e.parent, WRAP(expressions...), "NOT IN")
 }
 
 func (e *expressionInterfaceImpl) AS(alias string) projection {
diff --git a/sqlbuilder/expression_old_test.go b/sqlbuilder/expression_old_test.go
index 4077a2c..f4cdcc3 100644
--- a/sqlbuilder/expression_old_test.go
+++ b/sqlbuilder/expression_old_test.go
@@ -107,7 +107,7 @@ func (s *ExprSuite) TestOrExpr(c *gc.C) {
 }
 
 func (s *ExprSuite) TestAddExpr(c *gc.C) {
-	expr := Add(Literal(1), Literal(2), Literal(3))
+	expr := Add(literal(1), literal(2), literal(3))
 
 	buf := &bytes.Buffer{}
 
@@ -119,7 +119,7 @@ func (s *ExprSuite) TestAddExpr(c *gc.C) {
 }
 
 func (s *ExprSuite) TestSubExpr(c *gc.C) {
-	expr := Sub(Literal(1), Literal(2), Literal(3))
+	expr := Sub(literal(1), literal(2), literal(3))
 
 	buf := &bytes.Buffer{}
 
@@ -131,7 +131,7 @@ func (s *ExprSuite) TestSubExpr(c *gc.C) {
 }
 
 func (s *ExprSuite) TestMulExpr(c *gc.C) {
-	expr := Mul(Literal(1), Literal(2), Literal(3))
+	expr := Mul(literal(1), literal(2), literal(3))
 
 	buf := &bytes.Buffer{}
 
@@ -143,7 +143,7 @@ func (s *ExprSuite) TestMulExpr(c *gc.C) {
 }
 
 func (s *ExprSuite) TestDivExpr(c *gc.C) {
-	expr := Div(Literal(1), Literal(2), Literal(3))
+	expr := Div(literal(1), literal(2), literal(3))
 
 	buf := &bytes.Buffer{}
 
@@ -388,7 +388,7 @@ func (s *ExprSuite) TestColumnValue(c *gc.C) {
 }
 
 func (s *ExprSuite) TestBitwiseOr(c *gc.C) {
-	clause := BitOr(Literal(1), Literal(2))
+	clause := BitOr(literal(1), literal(2))
 
 	buf := &bytes.Buffer{}
 
@@ -400,7 +400,7 @@ func (s *ExprSuite) TestBitwiseOr(c *gc.C) {
 }
 
 func (s *ExprSuite) TestBitwiseAnd(c *gc.C) {
-	clause := BitAnd(Literal(1), Literal(2))
+	clause := BitAnd(literal(1), literal(2))
 
 	buf := &bytes.Buffer{}
 
@@ -412,7 +412,7 @@ func (s *ExprSuite) TestBitwiseAnd(c *gc.C) {
 }
 
 func (s *ExprSuite) TestBitwiseXor(c *gc.C) {
-	clause := BitXor(Literal(1), Literal(2))
+	clause := BitXor(literal(1), literal(2))
 
 	buf := &bytes.Buffer{}
 
@@ -424,7 +424,7 @@ func (s *ExprSuite) TestBitwiseXor(c *gc.C) {
 }
 
 func (s *ExprSuite) TestPlus(c *gc.C) {
-	clause := Plus(Literal(1), Literal(2))
+	clause := Plus(literal(1), literal(2))
 
 	buf := &bytes.Buffer{}
 
@@ -436,7 +436,7 @@ func (s *ExprSuite) TestPlus(c *gc.C) {
 }
 
 func (s *ExprSuite) TestMinus(c *gc.C) {
-	clause := Minus(Literal(1), Literal(2))
+	clause := Minus(literal(1), literal(2))
 
 	buf := &bytes.Buffer{}
 
diff --git a/sqlbuilder/expression_test.go b/sqlbuilder/expression_test.go
index 429410d..59289e5 100644
--- a/sqlbuilder/expression_test.go
+++ b/sqlbuilder/expression_test.go
@@ -60,3 +60,35 @@ func TestExpressionCAST_TO_TIMESTAMP(t *testing.T) {
 func TestExpressionCAST_TO_TIMESTAMPZ(t *testing.T) {
 	assertExpressionSerialize(t, table2Col3.CAST_TO_TIMESTAMPZ(), "table2.col3::timestamp with time zone")
 }
+
+func TestIN(t *testing.T) {
+
+	assertExpressionSerialize(t, Float(1.11).IN(table1.SELECT(table1Col1)),
+		`($1 IN ((
+     SELECT table1.col1 AS "table1.col1"
+     FROM db.table1
+)))`, float64(1.11))
+
+	assertExpressionSerialize(t, ROW(Int(12), table1Col1).IN(table2.SELECT(table2Col3, table3Col1)),
+		`(ROW($1, table1.col1) IN ((
+     SELECT table2.col3 AS "table2.col3",
+          table3.col1 AS "table3.col1"
+     FROM db.table2
+)))`, int64(12))
+}
+
+func TestNOT_IN(t *testing.T) {
+
+	assertExpressionSerialize(t, Float(1.11).NOT_IN(table1.SELECT(table1Col1)),
+		`($1 NOT IN ((
+     SELECT table1.col1 AS "table1.col1"
+     FROM db.table1
+)))`, float64(1.11))
+
+	assertExpressionSerialize(t, ROW(Int(12), table1Col1).NOT_IN(table2.SELECT(table2Col3, table3Col1)),
+		`(ROW($1, table1.col1) NOT IN ((
+     SELECT table2.col3 AS "table2.col3",
+          table3.col1 AS "table3.col1"
+     FROM db.table2
+)))`, int64(12))
+}
diff --git a/sqlbuilder/func_expression.go b/sqlbuilder/func_expression.go
index b2453ad..ab0f523 100644
--- a/sqlbuilder/func_expression.go
+++ b/sqlbuilder/func_expression.go
@@ -49,9 +49,6 @@ func (f *funcExpressionImpl) serialize(statement statementType, out *queryData,
 
 	return nil
 }
-func ROW(expressions ...expression) expression {
-	return newFunc("ROW", expressions, nil)
-}
 
 type boolFunc struct {
 	funcExpressionImpl
@@ -179,6 +176,10 @@ func newTimestampzFunc(name string, expressions ...expression) *timestampzFunc {
 	return timestampzFunc
 }
 
+func ROW(expressions ...expression) expression {
+	return newFunc("ROW", expressions, nil)
+}
+
 // ------------------ Mathematical functions ---------------//
 
 func ABSf(floatExpression FloatExpression) FloatExpression {
@@ -370,8 +371,8 @@ func DECODE(data StringExpression, format StringExpression) StringExpression {
 	return newStringFunc("DECODE", data, format)
 }
 
-//func FORMAT(formatStr StringExpression, formatArgs ...expression) StringExpression {
-//	args := []expression{formatStr}
+//func FORMAT(formatStr StringExpression, formatArgs ...expressions) StringExpression {
+//	args := []expressions{formatStr}
 //	args = append(args, formatArgs...)
 //	return newStringFunc("FORMAT", args...)
 //}
@@ -479,7 +480,7 @@ func CURRENT_TIME(precision ...int) TimezExpression {
 	var timezFunc *timezFunc
 
 	if len(precision) > 0 {
-		timezFunc = newTimezFunc("CURRENT_TIME", ConstantLiteral(precision[0]))
+		timezFunc = newTimezFunc("CURRENT_TIME", constLiteral(precision[0]))
 	} else {
 		timezFunc = newTimezFunc("CURRENT_TIME")
 	}
@@ -493,7 +494,7 @@ func CURRENT_TIMESTAMP(precision ...int) TimestampzExpression {
 	var timestampzFunc *timestampzFunc
 
 	if len(precision) > 0 {
-		timestampzFunc = newTimestampzFunc("CURRENT_TIMESTAMP", ConstantLiteral(precision[0]))
+		timestampzFunc = newTimestampzFunc("CURRENT_TIMESTAMP", constLiteral(precision[0]))
 	} else {
 		timestampzFunc = newTimestampzFunc("CURRENT_TIMESTAMP")
 	}
@@ -507,7 +508,7 @@ func LOCALTIME(precision ...int) TimeExpression {
 	var timeFunc *timeFunc
 
 	if len(precision) > 0 {
-		timeFunc = newTimeFunc("LOCALTIME", ConstantLiteral(precision[0]))
+		timeFunc = newTimeFunc("LOCALTIME", constLiteral(precision[0]))
 	} else {
 		timeFunc = newTimeFunc("LOCALTIME")
 	}
@@ -521,7 +522,7 @@ func LOCALTIMESTAMP(precision ...int) TimestampExpression {
 	var timestampFunc *timestampFunc
 
 	if len(precision) > 0 {
-		timestampFunc = newTimestampFunc("LOCALTIMESTAMP", ConstantLiteral(precision[0]))
+		timestampFunc = newTimestampFunc("LOCALTIMESTAMP", constLiteral(precision[0]))
 	} else {
 		timestampFunc = newTimestampFunc("LOCALTIMESTAMP")
 	}
diff --git a/sqlbuilder/insert_statement.go b/sqlbuilder/insert_statement.go
index 19f9104..a008bce 100644
--- a/sqlbuilder/insert_statement.go
+++ b/sqlbuilder/insert_statement.go
@@ -59,7 +59,7 @@ func (i *insertStatementImpl) VALUES(values ...interface{}) insertStatement {
 		if clause, ok := value.(clause); ok {
 			literalRow = append(literalRow, clause)
 		} else {
-			literalRow = append(literalRow, Literal(value))
+			literalRow = append(literalRow, literal(value))
 		}
 	}
 
@@ -97,7 +97,7 @@ func (i *insertStatementImpl) VALUES_MAPPING(data interface{}) insertStatement {
 			return i
 		}
 
-		rowValues = append(rowValues, Literal(structField.Interface()))
+		rowValues = append(rowValues, literal(structField.Interface()))
 	}
 
 	i.rows = append(i.rows, rowValues)
diff --git a/sqlbuilder/literal_expression.go b/sqlbuilder/literal_expression.go
index 54f4c8f..8bd2feb 100644
--- a/sqlbuilder/literal_expression.go
+++ b/sqlbuilder/literal_expression.go
@@ -9,15 +9,15 @@ type literalExpression struct {
 	constant bool
 }
 
-func Literal(value interface{}) *literalExpression {
+func literal(value interface{}) *literalExpression {
 	exp := literalExpression{value: value}
 	exp.expressionInterfaceImpl.parent = &exp
 
 	return &exp
 }
 
-func ConstantLiteral(value interface{}) *literalExpression {
-	exp := Literal(value)
+func constLiteral(value interface{}) *literalExpression {
+	exp := literal(value)
 	exp.constant = true
 
 	return exp
@@ -41,7 +41,7 @@ type integerLiteralExpression struct {
 func Int(value int64) IntegerExpression {
 	numLiteral := &integerLiteralExpression{}
 
-	numLiteral.literalExpression = *Literal(value)
+	numLiteral.literalExpression = *literal(value)
 
 	numLiteral.literalExpression.parent = numLiteral
 	numLiteral.integerInterfaceImpl.parent = numLiteral
@@ -58,7 +58,7 @@ type boolLiteralExpression struct {
 func Bool(value bool) BoolExpression {
 	boolLiteralExpression := boolLiteralExpression{}
 
-	boolLiteralExpression.literalExpression = *Literal(value)
+	boolLiteralExpression.literalExpression = *literal(value)
 	boolLiteralExpression.boolInterfaceImpl.parent = &boolLiteralExpression
 
 	return &boolLiteralExpression
@@ -72,7 +72,7 @@ type floatLiteral struct {
 
 func Float(value float64) FloatExpression {
 	floatLiteral := floatLiteral{}
-	floatLiteral.literalExpression = *Literal(value)
+	floatLiteral.literalExpression = *literal(value)
 
 	floatLiteral.floatInterfaceImpl.parent = &floatLiteral
 
@@ -87,7 +87,7 @@ type stringLiteral struct {
 
 func String(value string) StringExpression {
 	stringLiteral := stringLiteral{}
-	stringLiteral.literalExpression = *Literal(value)
+	stringLiteral.literalExpression = *literal(value)
 
 	stringLiteral.stringInterfaceImpl.parent = &stringLiteral
 
@@ -103,7 +103,7 @@ type timeLiteral struct {
 func Time(hour, minute, second, milliseconds int) TimeExpression {
 	timeLiteral := timeLiteral{}
 	timeStr := fmt.Sprintf("%02d:%02d:%02d.%03d", hour, minute, second, milliseconds)
-	timeLiteral.literalExpression = *Literal(timeStr)
+	timeLiteral.literalExpression = *literal(timeStr)
 
 	timeLiteral.timeInterfaceImpl.parent = &timeLiteral
 
@@ -119,7 +119,7 @@ type timezLiteral struct {
 func Timez(hour, minute, second, milliseconds, timezone int) TimezExpression {
 	timezLiteral := timezLiteral{}
 	timeStr := fmt.Sprintf("%02d:%02d:%02d.%03d %+03d", hour, minute, second, milliseconds, timezone)
-	timezLiteral.literalExpression = *Literal(timeStr)
+	timezLiteral.literalExpression = *literal(timeStr)
 
 	timezLiteral.timezInterfaceImpl.parent = &timezLiteral
 
@@ -135,7 +135,7 @@ type timestampLiteral struct {
 func Timestamp(year, month, day, hour, minute, second, milliseconds int) TimestampExpression {
 	timestampLiteral := timestampLiteral{}
 	timeStr := fmt.Sprintf("%04d-%02d-%02d %02d:%02d:%02d.%03d", year, month, day, hour, minute, second, milliseconds)
-	timestampLiteral.literalExpression = *Literal(timeStr)
+	timestampLiteral.literalExpression = *literal(timeStr)
 
 	timestampLiteral.timestampInterfaceImpl.parent = &timestampLiteral
 
@@ -153,7 +153,7 @@ func Timestampz(year, month, day, hour, minute, second, milliseconds, timezone i
 	timeStr := fmt.Sprintf("%04d-%02d-%02d %02d:%02d:%02d.%03d %+04d",
 		year, month, day, hour, minute, second, milliseconds, timezone)
 
-	timestampzLiteral.literalExpression = *Literal(timeStr)
+	timestampzLiteral.literalExpression = *literal(timeStr)
 
 	timestampzLiteral.timestampzInterfaceImpl.parent = &timestampzLiteral
 
@@ -170,7 +170,7 @@ func Date(year, month, day int) DateExpression {
 	dateLiteral := dateLiteral{}
 
 	timeStr := fmt.Sprintf("%04d-%02d-%02d", year, month, day)
-	dateLiteral.literalExpression = *Literal(timeStr)
+	dateLiteral.literalExpression = *literal(timeStr)
 	dateLiteral.dateInterfaceImpl.parent = &dateLiteral
 
 	return dateLiteral.CAST_TO_DATE()
@@ -211,3 +211,24 @@ func (n *starLiteral) serialize(statement statementType, out *queryData, options
 	out.writeString("*")
 	return nil
 }
+
+//---------------------------------------------------//
+
+type wrap struct {
+	expressionInterfaceImpl
+	expressions []expression
+}
+
+func (n *wrap) serialize(statement statementType, out *queryData, options ...serializeOption) error {
+	out.writeString("(")
+	err := serializeExpressionList(statement, n.expressions, ", ", out)
+	out.writeString(")")
+	return err
+}
+
+func WRAP(expression ...expression) expression {
+	wrap := &wrap{expressions: expression}
+	wrap.expressionInterfaceImpl.parent = wrap
+
+	return wrap
+}
diff --git a/sqlbuilder/operators.go b/sqlbuilder/operators.go
index c224e75..c7ddf6a 100644
--- a/sqlbuilder/operators.go
+++ b/sqlbuilder/operators.go
@@ -82,20 +82,12 @@ func Or(lhs, rhs expression) BoolExpression {
 	return newBinaryBoolExpression(lhs, rhs, "OR")
 }
 
-func Like(lhs, rhs expression) BoolExpression {
-	return newBinaryBoolExpression(lhs, rhs, "LIKE")
-}
-
-func LikeL(lhs expression, val string) BoolExpression {
-	return Like(lhs, Literal(val))
-}
-
 func Regexp(lhs, rhs expression) BoolExpression {
 	return newBinaryBoolExpression(lhs, rhs, "REGEXP")
 }
 
 func RegexpL(lhs expression, val string) BoolExpression {
-	return Regexp(lhs, Literal(val))
+	return Regexp(lhs, literal(val))
 }
 
 func EXISTS(subQuery selectStatement) BoolExpression {
diff --git a/sqlbuilder/operators_test.go b/sqlbuilder/operators_test.go
index 568639b..9b13e73 100644
--- a/sqlbuilder/operators_test.go
+++ b/sqlbuilder/operators_test.go
@@ -2,6 +2,14 @@ package sqlbuilder
 
 import "testing"
 
+func TestOperatorNOT(t *testing.T) {
+	notExpression := NOT(Int(2).EQ(Int(1)))
+
+	assertExpressionSerialize(t, notExpression, "NOT ($1 = $2)", int64(2), int64(1))
+	assertProjectionSerialize(t, notExpression.AS("alias_not_expression"), `NOT ($1 = $2) AS "alias_not_expression"`, int64(2), int64(1))
+	assertExpressionSerialize(t, notExpression.AND(Int(4).EQ(Int(5))), `(NOT ($1 = $2) AND ($3 = $4))`, int64(2), int64(1), int64(4), int64(5))
+}
+
 func TestCase1(t *testing.T) {
 	query := CASE().
 		WHEN(table3Col1.EQ(Int(1))).THEN(table3Col1.ADD(Int(1))).
diff --git a/sqlbuilder/select_statement.go b/sqlbuilder/select_statement.go
index d2ec6ed..8555ba1 100644
--- a/sqlbuilder/select_statement.go
+++ b/sqlbuilder/select_statement.go
@@ -127,18 +127,12 @@ func (s *selectStatementImpl) serializeImpl(out *queryData) error {
 		return err
 	}
 
-	if s.table == nil {
-		return errors.Newf("nil tableName.")
+	if s.table != nil {
+		if err := out.writeFrom(select_statement, s.table); err != nil {
+			return err
+		}
 	}
 
-	if err := out.writeFrom(select_statement, s.table); err != nil {
-		return err
-	}
-
-	//if err := s.table.serialize(select_statement, out); err != nil {
-	//	return err
-	//}
-
 	if s.where != nil {
 		err := out.writeWhere(select_statement, s.where)
 
diff --git a/sqlbuilder/statement_test.go b/sqlbuilder/statement_test.go
index 095603d..7574fe0 100644
--- a/sqlbuilder/statement_test.go
+++ b/sqlbuilder/statement_test.go
@@ -261,13 +261,13 @@ func (s *StmtSuite) TestInsertNilValue(c *gc.C) {
 }
 
 func (s *StmtSuite) TestInsertNilColumn(c *gc.C) {
-	_, err := table1.INSERT(nil).Add(Literal(1)).String()
+	_, err := table1.INSERT(nil).Add(literal(1)).String()
 
 	c.Assert(err, gc.NotNil)
 }
 
 func (s *StmtSuite) TestInsertSingleValue(c *gc.C) {
-	sql, err := table1.INSERT(table1Col1).Add(Literal(1)).String()
+	sql, err := table1.INSERT(table1Col1).Add(literal(1)).String()
 	c.Assert(err, gc.IsNil)
 
 	c.Assert(
@@ -279,7 +279,7 @@ func (s *StmtSuite) TestInsertSingleValue(c *gc.C) {
 func (s *StmtSuite) TestInsertDate(c *gc.C) {
 	date := time.Date(1999, 1, 2, 3, 4, 5, 0, time.UTC)
 
-	sql, err := table1.INSERT(table1ColTime).Add(Literal(date)).String()
+	sql, err := table1.INSERT(table1ColTime).Add(literal(date)).String()
 	c.Assert(err, gc.IsNil)
 
 	c.Assert(
@@ -290,7 +290,7 @@ func (s *StmtSuite) TestInsertDate(c *gc.C) {
 }
 
 func (s *StmtSuite) TestInsertIgnore(c *gc.C) {
-	stmt := table1.INSERT(table1Col1).Add(Literal(1)).IgnoreDuplicates(true)
+	stmt := table1.INSERT(table1Col1).Add(literal(1)).IgnoreDuplicates(true)
 	sql, err := stmt.String()
 	c.Assert(err, gc.IsNil)
 
@@ -302,7 +302,7 @@ func (s *StmtSuite) TestInsertIgnore(c *gc.C) {
 
 func (s *StmtSuite) TestInsertMultipleValues(c *gc.C) {
 	stmt := table1.INSERT(table1Col1, table1ColFloat, table1Col3)
-	stmt.Add(Literal(1), Literal(2), Literal(3))
+	stmt.Add(literal(1), literal(2), literal(3))
 
 	sql, err := stmt.String()
 	c.Assert(err, gc.IsNil)
@@ -317,9 +317,9 @@ func (s *StmtSuite) TestInsertMultipleValues(c *gc.C) {
 
 func (s *StmtSuite) TestInsertMultipleRows(c *gc.C) {
 	stmt := table1.INSERT(table1Col1, table1ColFloat)
-	stmt.Add(Literal(1), Literal(2))
-	stmt.Add(Literal(11), Literal(22))
-	stmt.Add(Literal(111), Literal(222))
+	stmt.Add(literal(1), literal(2))
+	stmt.Add(literal(11), literal(22))
+	stmt.Add(literal(111), literal(222))
 
 	sql, err := stmt.String()
 	c.Assert(err, gc.IsNil)
@@ -334,8 +334,8 @@ func (s *StmtSuite) TestInsertMultipleRows(c *gc.C) {
 
 func (s *StmtSuite) TestOnDuplicateKeyUpdateNilCol(c *gc.C) {
 	stmt := table1.INSERT(table1Col1, table1ColFloat)
-	stmt.Add(Literal(1), Literal(2))
-	stmt.AddOnDuplicateKeyUpdate(nil, Literal(3))
+	stmt.Add(literal(1), literal(2))
+	stmt.AddOnDuplicateKeyUpdate(nil, literal(3))
 
 	_, err := stmt.String()
 	c.Assert(err, gc.NotNil)
@@ -343,7 +343,7 @@ func (s *StmtSuite) TestOnDuplicateKeyUpdateNilCol(c *gc.C) {
 
 func (s *StmtSuite) TestOnDuplicateKeyUpdateNilExpr(c *gc.C) {
 	stmt := table1.INSERT(table1Col1, table1ColFloat)
-	stmt.Add(Literal(1), Literal(2))
+	stmt.Add(literal(1), literal(2))
 	stmt.AddOnDuplicateKeyUpdate(table1Col1, nil)
 
 	_, err := stmt.String()
@@ -352,8 +352,8 @@ func (s *StmtSuite) TestOnDuplicateKeyUpdateNilExpr(c *gc.C) {
 
 func (s *StmtSuite) TestOnDuplicateKeyUpdateSingle(c *gc.C) {
 	stmt := table1.INSERT(table1Col1, table1ColFloat)
-	stmt.Add(Literal(1), Literal(2))
-	stmt.AddOnDuplicateKeyUpdate(table1Col3, Literal(3))
+	stmt.Add(literal(1), literal(2))
+	stmt.AddOnDuplicateKeyUpdate(table1Col3, literal(3))
 
 	sql, err := stmt.String()
 	c.Assert(err, gc.IsNil)
@@ -369,9 +369,9 @@ func (s *StmtSuite) TestOnDuplicateKeyUpdateSingle(c *gc.C) {
 
 func (s *StmtSuite) TestOnDuplicateKeyUpdateMulti(c *gc.C) {
 	stmt := table1.INSERT(table1Col1, table1ColFloat)
-	stmt.Add(Literal(1), Literal(2))
-	stmt.AddOnDuplicateKeyUpdate(table1Col3, Literal(3))
-	stmt.AddOnDuplicateKeyUpdate(table1ColFloat, Literal(4))
+	stmt.Add(literal(1), literal(2))
+	stmt.AddOnDuplicateKeyUpdate(table1Col3, literal(3))
+	stmt.AddOnDuplicateKeyUpdate(table1ColFloat, literal(4))
 
 	sql, err := stmt.String()
 	c.Assert(err, gc.IsNil)
diff --git a/sqlbuilder/test_utils.go b/sqlbuilder/test_utils.go
index 9fc3d1a..34ef813 100644
--- a/sqlbuilder/test_utils.go
+++ b/sqlbuilder/test_utils.go
@@ -58,3 +58,13 @@ func assertExpressionSerialize(t *testing.T, expression expression, query string
 	assert.DeepEqual(t, out.buff.String(), query)
 	assert.DeepEqual(t, out.args, args)
 }
+
+func assertProjectionSerialize(t *testing.T, projection projection, query string, args ...interface{}) {
+	out := queryData{}
+	err := projection.serializeForProjection(select_statement, &out)
+
+	assert.NilError(t, err)
+
+	assert.DeepEqual(t, out.buff.String(), query)
+	assert.DeepEqual(t, out.args, args)
+}
diff --git a/sqlbuilder/time_expression.go b/sqlbuilder/time_expression.go
index d4c4e10..bf81e98 100644
--- a/sqlbuilder/time_expression.go
+++ b/sqlbuilder/time_expression.go
@@ -69,5 +69,5 @@ func newPrefixTimeExpression(operator string, expression expression) TimeExpress
 }
 
 func INTERVAL(interval string) expression {
-	return newPrefixTimeExpression("INTERVAL", Literal(interval))
+	return newPrefixTimeExpression("INTERVAL", literal(interval))
 }
diff --git a/sqlbuilder/update_statement.go b/sqlbuilder/update_statement.go
index 9a60814..b54216d 100644
--- a/sqlbuilder/update_statement.go
+++ b/sqlbuilder/update_statement.go
@@ -35,7 +35,7 @@ func (u *updateStatementImpl) SET(values ...interface{}) updateStatement {
 		if clause, ok := value.(clause); ok {
 			u.updateValues = append(u.updateValues, clause)
 		} else {
-			u.updateValues = append(u.updateValues, Literal(value))
+			u.updateValues = append(u.updateValues, literal(value))
 		}
 	}
 
diff --git a/sqlbuilder/update_statement_test.go b/sqlbuilder/update_statement_test.go
index 1ff95ce..7b4ba79 100644
--- a/sqlbuilder/update_statement_test.go
+++ b/sqlbuilder/update_statement_test.go
@@ -34,7 +34,7 @@ RETURNING table1.col1 AS "table1.col1";
 }
 
 //func (s *StmtSuite) TestUpdateNilColumn(c *gc.C) {
-//	stmt := table1.UPDATE().SET(nil, Literal(1))
+//	stmt := table1.UPDATE().SET(nil, literal(1))
 //	_, err := stmt.String()
 //	c.Assert(err, gc.NotNil)
 //}
@@ -46,13 +46,13 @@ RETURNING table1.col1 AS "table1.col1";
 //}
 //
 //func (s *StmtSuite) TestUpdateUnconditionally(c *gc.C) {
-//	stmt := table1.UPDATE().SET(table1Col1, Literal(1))
+//	stmt := table1.UPDATE().SET(table1Col1, literal(1))
 //	_, err := stmt.String()
 //	c.Assert(err, gc.NotNil)
 //}
 //
 //func (s *StmtSuite) TestUpdateSingleValue(c *gc.C) {
-//	stmt := table1.UPDATE().SET(table1Col1, Literal(1))
+//	stmt := table1.UPDATE().SET(table1Col1, literal(1))
 //	stmt.WHERE(EqString(table1ColFloat, 2))
 //	sql, err := stmt.String()
 //	c.Assert(err, gc.IsNil)
@@ -64,7 +64,7 @@ RETURNING table1.col1 AS "table1.col1";
 //}
 //
 //func (s *StmtSuite) TestUpdateUsingDeferredLookupColumns(c *gc.C) {
-//	stmt := table1.UPDATE().SET(table1.C("col1"), Literal(1))
+//	stmt := table1.UPDATE().SET(table1.C("col1"), literal(1))
 //	stmt.WHERE(EqString(table1ColFloat, 2))
 //	sql, err := stmt.String()
 //	c.Assert(err, gc.IsNil)
@@ -77,8 +77,8 @@ RETURNING table1.col1 AS "table1.col1";
 //
 //func (s *StmtSuite) TestUpdateMultiValues(c *gc.C) {
 //	stmt := table1.UPDATE()
-//	stmt.SET(table1Col1, Literal(1))
-//	stmt.SET(table1ColFloat, Literal(2))
+//	stmt.SET(table1Col1, literal(1))
+//	stmt.SET(table1ColFloat, literal(2))
 //	stmt.WHERE(EqString(table1ColFloat, 3))
 //	sql, err := stmt.String()
 //	c.Assert(err, gc.IsNil)
@@ -92,7 +92,7 @@ RETURNING table1.col1 AS "table1.col1";
 //}
 //
 //func (s *StmtSuite) TestUpdateWithOrderBy(c *gc.C) {
-//	stmt := table1.UPDATE().SET(table1Col1, Literal(1))
+//	stmt := table1.UPDATE().SET(table1Col1, literal(1))
 //	stmt.WHERE(EqString(table1ColFloat, 2))
 //	stmt.ORDER_BY(table1ColFloat)
 //	sql, err := stmt.String()
@@ -108,7 +108,7 @@ RETURNING table1.col1 AS "table1.col1";
 //}
 //
 //func (s *StmtSuite) TestUpdateWithLimit(c *gc.C) {
-//	stmt := table1.UPDATE().SET(table1Col1, Literal(1))
+//	stmt := table1.UPDATE().SET(table1Col1, literal(1))
 //	stmt.WHERE(EqString(table1ColFloat, 2))
 //	stmt.LIMIT(5)
 //	sql, err := stmt.String()
diff --git a/tests/scan_test.go b/tests/scan_test.go
index 201f3f1..0899cd9 100644
--- a/tests/scan_test.go
+++ b/tests/scan_test.go
@@ -269,7 +269,7 @@ func TestScanToNestedStruct(t *testing.T) {
 		query := Inventory.
 			INNER_JOIN(Film, Inventory.FilmID.EQ(Film.FilmID)).
 			INNER_JOIN(Store, Inventory.StoreID.EQ(Store.StoreID)).
-			SELECT(Inventory.AllColumns, Film.AllColumns, Store.AllColumns, Literal("").AS("actor.first_name")).
+			SELECT(Inventory.AllColumns, Film.AllColumns, Store.AllColumns, String("").AS("actor.first_name")).
 			WHERE(Inventory.InventoryID.EQ(Int(1)))
 
 		dest := struct {
diff --git a/tests/select_test.go b/tests/select_test.go
index da80a48..b1fed8f 100644
--- a/tests/select_test.go
+++ b/tests/select_test.go
@@ -1086,10 +1086,10 @@ LIMIT 20;
 `
 	query := Payment.SELECT(
 		CASE(Payment.StaffID).
-			WHEN(Int(1)).THEN(Literal("ONE")).
-			WHEN(Int(2)).THEN(Literal("TWO")).
-			WHEN(Int(3)).THEN(Literal("THREE")).
-			ELSE(Literal("OTHER")).AS("staff_id_num"),
+			WHEN(Int(1)).THEN(String("ONE")).
+			WHEN(Int(2)).THEN(String("TWO")).
+			WHEN(Int(3)).THEN(String("THREE")).
+			ELSE(String("OTHER")).AS("staff_id_num"),
 	).
 		ORDER_BY(Payment.PaymentID.ASC()).
 		LIMIT(20)
diff --git a/tests/types_test.go b/tests/types_test.go
index 0687e44..de7bfee 100644
--- a/tests/types_test.go
+++ b/tests/types_test.go
@@ -29,6 +29,10 @@ func TestExpressionOperators(t *testing.T) {
 	query := AllTypes.SELECT(
 		AllTypes.Integer.IS_NULL(),
 		AllTypes.Timestamp.IS_NOT_NULL(),
+		AllTypes.SmallintPtr.IN(Int(11), Int(22), NULL),
+		AllTypes.SmallintPtr.IN(AllTypes.SELECT(AllTypes.IntegerPtr)),
+		AllTypes.SmallintPtr.NOT_IN(Int(11), Int(22), NULL),
+		AllTypes.SmallintPtr.NOT_IN(AllTypes.SELECT(AllTypes.IntegerPtr)),
 
 		String("TRUE").CAST_TO_BOOL(),
 		String("111").CAST_TO_INTEGER(),