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mysql.go
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mysql.go
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package parser
import (
"errors"
"fmt"
"github.com/xwb1989/sqlparser"
)
type mySQL struct {
SQL string
stmt sqlparser.Statement
}
func NewMySQL(sql string) (*mySQL, error) {
stmt, err := sqlparser.Parse(sql)
if err != nil {
return nil, err
}
return &mySQL{
SQL: sql,
stmt: stmt,
}, nil
}
func (m *mySQL) Type() (Type, error) {
switch m.stmt.(type) {
case *sqlparser.Select:
return TypeSelect, nil
case *sqlparser.Insert:
return TypeInsert, nil
case *sqlparser.Update:
return TypeUpdate, nil
case *sqlparser.Delete:
return TypeDelete, nil
default:
return 0, errors.New("sql parser: unsupported sql type")
}
}
func (m *mySQL) SelectColumns() ([]*Column, error) {
stmt, ok := m.stmt.(*sqlparser.Select)
if !ok {
return []*Column{}, errors.New("sql parser: not a select query")
}
columns := make([]*Column, 0, len(stmt.SelectExprs))
for _, selectExpr := range stmt.SelectExprs {
column, err := m.selectColumn(selectExpr)
if err != nil {
return columns, err
}
columns = append(columns, column)
}
return columns, nil
}
func (m *mySQL) selectColumn(selectExpr sqlparser.SelectExpr) (*Column, error) {
column := &Column{}
switch expr := selectExpr.(type) {
case *sqlparser.StarExpr:
column.Alias = "*"
column.TableQualifier = expr.TableName.Name.String()
case *sqlparser.AliasedExpr:
as := expr.As.String()
if len(as) > 0 {
column.Alias = as
column.TableQualifier = ""
} else {
switch aliasedExprExpr := expr.Expr.(type) {
case *sqlparser.ColName:
column.Alias = aliasedExprExpr.Name.String()
column.TableQualifier = aliasedExprExpr.Qualifier.Name.String()
default:
return column, fmt.Errorf("sql parser: unsupported column expr [%T]", expr)
}
}
default:
return column, fmt.Errorf("sql parser: unsupported column expr [%T]", expr)
}
return column, nil
}