SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Subquery (alias a) (children 1)
     SelectWithUnionQuery (children 1)
      ExpressionList (children 1)
       SelectQuery (children 2)
        ExpressionList (children 1)
         Function groupConcat (children 2)
          ExpressionList (children 1)
           Identifier st
          ExpressionList (children 1)
           Literal \',\'
        TablesInSelectQuery (children 1)
         TablesInSelectQueryElement (children 1)
          TableExpression (children 1)
           TableIdentifier t
    Subquery (alias b) (children 1)
     SelectWithUnionQuery (children 1)
      ExpressionList (children 1)
       SelectQuery (children 2)
        ExpressionList (children 1)
         Function groupConcat (children 2)
          ExpressionList (children 1)
           Function CAST (children 1)
            ExpressionList (children 2)
             Identifier st
             Literal \'String\'
          ExpressionList (children 1)
           Literal \',\'
        TablesInSelectQuery (children 1)
         TablesInSelectQueryElement (children 1)
          TableExpression (children 1)
           TableIdentifier t
   ExpressionList (children 1)
    Function equals (children 1)
     ExpressionList (children 2)
      Identifier a
      Identifier b
