SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function explain_index_equals (children 1)
       ExpressionList (children 3)
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier use_idx_fixed
          Literal UInt64_1
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier filter
          Literal \'K3\'
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier value
          Function toFixedString (children 1)
           ExpressionList (children 2)
            Literal \'V2\'
            Literal UInt64_2
