Add support for INSERT select query.

sqlbuilder/insert_statement.go

@@ -20,6 +20,8 @@ type InsertStatement interface {
 
 	RETURNING(column ...Expression) InsertStatement
 
+	QUERY(selectStatement SelectStatement) InsertStatement
+
 	Execute(db types.Db) (sql.Result, error)
 }
 
@@ -27,7 +29,7 @@ func newInsertStatement(t WritableTable, columns ...Column) InsertStatement {
 	return &insertStatementImpl{
 		table:     t,
 		columns:   columns,
-		rows:      make([][]Expression, 0, 1),
+		rows:      make([][]Clause, 0, 1),
 		returning: make([]Expression, 0, 1),
 	}
 }
@@ -40,7 +42,8 @@ type columnAssignment struct {
 type insertStatementImpl struct {
 	table     WritableTable
 	columns   []Column
-	rows      [][]Expression
+	rows      [][]Clause
+	query     SelectStatement
 	returning []Expression
 
 	errors []string
@@ -58,23 +61,15 @@ func (i *insertStatementImpl) Execute(db types.Db) (res sql.Result, err error) {
 	return
 }
 
-//func (i *insertStatementImpl) ExecuteInTx(tx *sql.Tx) (res sql.Result, err error) {
-//	query, err := i.String()
-//
-//	if err != nil {
-//		return
-//	}
-//
-//	res, err = tx.Exec(query)
-//
-//	return
-//}
-
 func (s *insertStatementImpl) VALUES(values ...interface{}) InsertStatement {
-	literalRow := []Expression{}
+	literalRow := []Clause{}
 
 	for _, value := range values {
-		literalRow = append(literalRow, Literal(value))
+		if clause, ok := value.(Clause); ok {
+			literalRow = append(literalRow, clause)
+		} else {
+			literalRow = append(literalRow, Literal(value))
+		}
 	}
 
 	s.rows = append(s.rows, literalRow)
@@ -98,7 +93,7 @@ func (i *insertStatementImpl) VALUES_MAPPING(data interface{}) InsertStatement {
 		return i
 	}
 
-	rowValues := []Expression{}
+	rowValues := []Clause{}
 
 	for _, column := range i.columns {
 		columnName := column.Name()
@@ -125,6 +120,12 @@ func (i *insertStatementImpl) RETURNING(column ...Expression) InsertStatement {
 	return i
 }
 
+func (i *insertStatementImpl) QUERY(selectStatement SelectStatement) InsertStatement {
+	i.query = selectStatement
+
+	return i
+}
+
 func (i *insertStatementImpl) addError(err string) {
 	i.errors = append(i.errors, err)
 }
@@ -144,63 +145,73 @@ func (s *insertStatementImpl) String() (sql string, err error) {
 
 	buf.WriteString(s.table.SchemaName() + "." + s.table.TableName())
 
-	if len(s.columns) == 0 {
-		return "", errors.Newf(
-			"No column specified.  Generated sql: %s",
-			buf.String())
-	}
-
-	_, _ = buf.WriteString(" (")
-	for i, col := range s.columns {
-		if i > 0 {
-			_ = buf.WriteByte(',')
-		}
-
-		if col == nil {
-			return "", errors.Newf(
-				"nil column in columns list.  Generated sql: %s",
-				buf.String())
-		}
-
-		buf.WriteString(col.Name())
-	}
-
-	if len(s.rows) == 0 {
-		return "", errors.Newf(
-			"No row specified.  Generated sql: %s",
-			buf.String())
-	}
-
-	_, _ = buf.WriteString(") VALUES (")
-	for row_i, row := range s.rows {
-		if row_i > 0 {
-			_, _ = buf.WriteString(", (")
-		}
-
-		if len(row) != len(s.columns) {
-			return "", errors.Newf(
-				"# of values does not match # of columns.  Generated sql: %s",
-				buf.String())
-		}
-
-		for col_i, value := range row {
-			if col_i > 0 {
+	if len(s.columns) > 0 {
+		_, _ = buf.WriteString(" (")
+		for i, col := range s.columns {
+			if i > 0 {
 				_ = buf.WriteByte(',')
 			}
 
-			if value == nil {
+			if col == nil {
 				return "", errors.Newf(
-					"nil value in row %d col %d.  Generated sql: %s",
-					row_i,
-					col_i,
+					"nil column in columns list.  Generated sql: %s",
 					buf.String())
 			}
 
-			if err = value.SerializeSql(buf); err != nil {
-				return
-			}
+			buf.WriteString(col.Name())
+		}
+
+		buf.WriteString(") ")
+	}
+
+	if len(s.rows) == 0 && s.query == nil {
+		return "", errors.Newf("No row or query  specified.  Generated sql: %s", buf.String())
+	}
+
+	if len(s.rows) > 0 && s.query != nil {
+		return "", errors.Newf("Only new rows or query has to be specified.  Generated sql: %s", buf.String())
+	}
+
+	if len(s.rows) > 0 {
+		_, _ = buf.WriteString("VALUES (")
+		for row_i, row := range s.rows {
+			if row_i > 0 {
+				_, _ = buf.WriteString(", (")
+			}
+
+			if len(row) != len(s.columns) {
+				return "", errors.Newf(
+					"# of values does not match # of columns.  Generated sql: %s",
+					buf.String())
+			}
+
+			for col_i, value := range row {
+				if col_i > 0 {
+					_ = buf.WriteByte(',')
+				}
+
+				if value == nil {
+					return "", errors.Newf(
+						"nil value in row %d col %d.  Generated sql: %s",
+						row_i,
+						col_i,
+						buf.String())
+				}
+
+				if err = value.SerializeSql(buf); err != nil {
+					return
+				}
+			}
+			_ = buf.WriteByte(')')
+		}
+	}
+
+	if s.query != nil {
+		err = s.query.SerializeSql(buf)
+
+		if err != nil {
+			return
 		}
-		_ = buf.WriteByte(')')
 	}
 
 	if len(s.returning) > 0 {