how to get the table names from BinaryOperationExpr of where clause

[baichuanyang]

Question

Hi.

i would like to parse a kind of query like:

select * from a inner join b on a.col1 == b.col1 inner join c on b.col2 == c.col2 where a.col3 = 1 and b.col4 = 5

and i got two *ast.BinaryOperationExpr of the where clause a.col3 = 1 and b.col4 = 5. however, that expression only contained *ast.ColumnNameExpr and *driver.ValueExpr and ignored the *ast.TableSource.

may i know how to get the table names?

thanks

[lance6716]

you can take a look at type ColumnName

parser/ast/expressions.go

Lines 558 to 569 in 94275e8

	// ColumnNameExpr represents a column name expression.
	type ColumnNameExpr struct {
	exprNode
	// Name is the referenced column name.
	Name *ColumnName
	// Refer is the result field the column name refers to.
	// The value of Refer.Expr is used as the value of the expression.
	Refer *ResultField
	}

[cjphaha]

you can take a look at type ColumnName

parser/ast/expressions.go

Lines 558 to 569 in 94275e8

	// ColumnNameExpr represents a column name expression.
	type ColumnNameExpr struct {
	exprNode
	// Name is the referenced column name.
	Name *ColumnName
	// Refer is the result field the column name refers to.
	// The value of Refer.Expr is used as the value of the expression.
	Refer *ResultField
	}

But this will cause many duplicate ColumnName to appear. Is there any way to reduce duplication?