diff --git a/internal/jet/clause.go b/internal/jet/clause.go
index a6a49d8..446a545 100644
--- a/internal/jet/clause.go
+++ b/internal/jet/clause.go
@@ -217,12 +217,13 @@ func (f *ClauseFor) Serialize(statementType StatementType, out *SQLBuilder, opti
 
 // ClauseSetStmtOperator struct
 type ClauseSetStmtOperator struct {
-	Operator string
-	All      bool
-	Selects  []SerializerStatement
-	OrderBy  ClauseOrderBy
-	Limit    ClauseLimit
-	Offset   ClauseOffset
+	Operator       string
+	All            bool
+	Selects        []SerializerStatement
+	OrderBy        ClauseOrderBy
+	Limit          ClauseLimit
+	Offset         ClauseOffset
+	SkipSelectWrap bool
 }
 
 // Projections returns set of projections for ClauseSetStmtOperator
@@ -242,6 +243,10 @@ func (s *ClauseSetStmtOperator) Serialize(statementType StatementType, out *SQLB
 	for i, selectStmt := range s.Selects {
 		out.NewLine()
 		if i > 0 {
+			if s.SkipSelectWrap {
+				out.NewLine()
+			}
+
 			out.WriteString(s.Operator)
 
 			if s.All {
@@ -254,7 +259,11 @@ func (s *ClauseSetStmtOperator) Serialize(statementType StatementType, out *SQLB
 			panic("jet: select statement of '" + s.Operator + "' is nil")
 		}
 
-		selectStmt.serialize(statementType, out, FallTrough(options)...)
+		if s.SkipSelectWrap {
+			options = append(FallTrough(options), NoWrap)
+		}
+
+		selectStmt.serialize(statementType, out, options...)
 	}
 
 	s.OrderBy.Serialize(statementType, out)
@@ -360,10 +369,6 @@ type ClauseValuesQuery struct {
 
 // Serialize serializes clause into SQLBuilder
 func (v *ClauseValuesQuery) Serialize(statementType StatementType, out *SQLBuilder, options ...SerializeOption) {
-	if len(v.Rows) == 0 && v.Query == nil {
-		panic("jet: VALUES or QUERY has to be specified for INSERT statement")
-	}
-
 	if len(v.Rows) > 0 && v.Query != nil {
 		panic("jet: VALUES or QUERY has to be specified for INSERT statement")
 	}
@@ -405,7 +410,8 @@ func (v *ClauseValues) Serialize(statementType StatementType, out *SQLBuilder, o
 
 // ClauseQuery struct
 type ClauseQuery struct {
-	Query SerializerStatement
+	Query          SerializerStatement
+	SkipSelectWrap bool
 }
 
 // Serialize serializes clause into SQLBuilder
@@ -414,7 +420,11 @@ func (v *ClauseQuery) Serialize(statementType StatementType, out *SQLBuilder, op
 		return
 	}
 
-	v.Query.serialize(statementType, out, FallTrough(options)...)
+	if v.SkipSelectWrap {
+		options = append(FallTrough(options), NoWrap)
+	}
+
+	v.Query.serialize(statementType, out, options...)
 }
 
 // ClauseDelete struct
@@ -561,3 +571,26 @@ type KeywordClause struct {
 func (k KeywordClause) Serialize(statementType StatementType, out *SQLBuilder, options ...SerializeOption) {
 	k.serialize(statementType, out, FallTrough(options)...)
 }
+
+// ClauseReturning  type
+type ClauseReturning struct {
+	ProjectionList []Projection
+}
+
+// Serialize for ClauseReturning
+func (r *ClauseReturning) Serialize(statementType StatementType, out *SQLBuilder, options ...SerializeOption) {
+	if len(r.ProjectionList) == 0 {
+		return
+	}
+
+	out.NewLine()
+	out.WriteString("RETURNING")
+	out.IncreaseIdent()
+	out.WriteProjections(statementType, r.ProjectionList)
+	out.DecreaseIdent()
+}
+
+// Projections for ClauseReturning
+func (r ClauseReturning) Projections() ProjectionList {
+	return r.ProjectionList
+}
diff --git a/postgres/clause.go b/postgres/clause.go
index 6174d4f..3a23fd0 100644
--- a/postgres/clause.go
+++ b/postgres/clause.go
@@ -4,33 +4,10 @@ import (
 	"github.com/go-jet/jet/v2/internal/jet"
 )
 
-type clauseReturning struct {
-	ProjectionList []jet.Projection
-}
-
-func (r *clauseReturning) Serialize(statementType jet.StatementType, out *jet.SQLBuilder, options ...jet.SerializeOption) {
-	if len(r.ProjectionList) == 0 {
-		return
-	}
-
-	out.NewLine()
-	out.WriteString("RETURNING")
-	out.IncreaseIdent()
-	out.WriteProjections(statementType, r.ProjectionList)
-	out.DecreaseIdent()
-}
-
-func (r clauseReturning) Projections() ProjectionList {
-	return r.ProjectionList
-}
-
-// ========================================== //
-
 type onConflict interface {
 	ON_CONSTRAINT(name string) conflictTarget
 	WHERE(indexPredicate BoolExpression) conflictTarget
-	DO_NOTHING() InsertStatement
-	DO_UPDATE(action conflictAction) InsertStatement
+	conflictTarget
 }
 
 type conflictTarget interface {
diff --git a/postgres/delete_statement.go b/postgres/delete_statement.go
index ca2816c..2bfbd8c 100644
--- a/postgres/delete_statement.go
+++ b/postgres/delete_statement.go
@@ -16,7 +16,7 @@ type deleteStatementImpl struct {
 
 	Delete    jet.ClauseStatementBegin
 	Where     jet.ClauseWhere
-	Returning clauseReturning
+	Returning jet.ClauseReturning
 }
 
 func newDeleteStatement(table WritableTable) DeleteStatement {
diff --git a/postgres/insert_statement.go b/postgres/insert_statement.go
index a134a12..763e533 100644
--- a/postgres/insert_statement.go
+++ b/postgres/insert_statement.go
@@ -22,7 +22,11 @@ type InsertStatement interface {
 func newInsertStatement(table WritableTable, columns []jet.Column) InsertStatement {
 	newInsert := &insertStatementImpl{}
 	newInsert.SerializerStatement = jet.NewStatementImpl(Dialect, jet.InsertStatementType, newInsert,
-		&newInsert.Insert, &newInsert.ValuesQuery, &newInsert.OnConflict, &newInsert.Returning)
+		&newInsert.Insert,
+		&newInsert.ValuesQuery,
+		&newInsert.OnConflict,
+		&newInsert.Returning,
+	)
 
 	newInsert.Insert.Table = table
 	newInsert.Insert.Columns = columns
@@ -35,7 +39,7 @@ type insertStatementImpl struct {
 
 	Insert      jet.ClauseInsert
 	ValuesQuery jet.ClauseValuesQuery
-	Returning   clauseReturning
+	Returning   jet.ClauseReturning
 	OnConflict  onConflictClause
 }
 
diff --git a/postgres/insert_statement_test.go b/postgres/insert_statement_test.go
index fd3a76c..ad687b5 100644
--- a/postgres/insert_statement_test.go
+++ b/postgres/insert_statement_test.go
@@ -8,7 +8,6 @@ import (
 )
 
 func TestInvalidInsert(t *testing.T) {
-	assertStatementSqlErr(t, table1.INSERT(table1Col1), "jet: VALUES or QUERY has to be specified for INSERT statement")
 	assertStatementSqlErr(t, table1.INSERT(nil).VALUES(1), "jet: nil column in columns list")
 }
 
diff --git a/postgres/interval_expression.go b/postgres/interval_expression.go
index b8468cf..6f5ab58 100644
--- a/postgres/interval_expression.go
+++ b/postgres/interval_expression.go
@@ -116,7 +116,7 @@ func INTERVAL(quantityAndUnit ...quantityAndUnit) IntervalExpression {
 		panic("jet: invalid number of quantity and unit fields")
 	}
 
-	fields := []string{}
+	var fields []string
 
 	for i := 0; i < len(quantityAndUnit); i += 2 {
 		quantity := strconv.FormatFloat(quantityAndUnit[i], 'f', -1, 64)
diff --git a/postgres/update_statement.go b/postgres/update_statement.go
index 594efa4..58c5ba4 100644
--- a/postgres/update_statement.go
+++ b/postgres/update_statement.go
@@ -22,7 +22,7 @@ type updateStatementImpl struct {
 	Set       clauseSet
 	SetNew    jet.SetClauseNew
 	Where     jet.ClauseWhere
-	Returning clauseReturning
+	Returning jet.ClauseReturning
 }
 
 func newUpdateStatement(table WritableTable, columns []jet.Column) UpdateStatement {