SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 1) ExpressionList (children 2) Function leftPad (children 1) ExpressionList (children 2) Literal \'abc\' Literal UInt64_10 Function leftPad (children 1) ExpressionList (children 2) Literal \'abc\' Function CAST (children 1) ExpressionList (children 2) Literal \'10\' Literal \'Int32\'