SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 1)
    Identifier arr
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier index_test
   Function has (children 1)
    ExpressionList (children 2)
     Function arrayMap (children 1)
      ExpressionList (children 2)
       Function lambda (children 1)
        ExpressionList (children 2)
         Function tuple (children 1)
          ExpressionList (children 1)
           Identifier x
         Function lower (children 1)
          ExpressionList (children 1)
           Identifier x
       Identifier arr
     Function lower (children 1)
      ExpressionList (children 1)
       Literal \'a_12\'
   Set
