Explain EXPLAIN (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 4)
     Identifier lhs.id
     Identifier lhs.value_1
     Identifier rhs.id
     Identifier rhs.value_1
    TablesInSelectQuery (children 2)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table_1 (alias lhs)
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       TableIdentifier test_table_2 (alias rhs)
      TableJoin (children 1)
       Function and (children 1)
        ExpressionList (children 2)
         Function equals (children 1)
          ExpressionList (children 2)
           Identifier lhs.id
           Identifier rhs.id
         Function less (children 1)
          ExpressionList (children 2)
           Identifier lhs.value_2
           Identifier rhs.value_2
