Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     ColumnsRegexpMatcher (children 1)
      ColumnsTransformerList (children 2)
       ColumnsApplyTransformer
       ColumnsApplyTransformer
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier columns_transformers