SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Identifier number (alias char_code)
    Function extract (alias needle) (children 1)
     ExpressionList (children 2)
      Function concat (alias haystack) (children 1)
       ExpressionList (children 2)
        Function char (children 1)
         ExpressionList (children 1)
          Identifier char_code
        Literal \' key="v" \'
      Literal \'key="(.*?)"\'
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function numbers (children 1)
       ExpressionList (children 1)
        Literal UInt64_256