Incorrect association of ORDER BY in a union query

[sivaraam]

Describe the bug
The ORDER BY present in the end of a UNION query should be associated with the UNION query as a whole. Currently, it is being associated with the last SELECT query in the UNION.

To Reproduce
Steps to reproduce the behavior:

1. Example SQL

SELECT * FROM table1 UNION SELECT * FROM table2 ORDER BY col

2. Parsing this SQL using JSqlParser with this statements

        Select unionQuery = (Select) CCJSqlParserUtil.parse("SELECT * FROM table1 UNION SELECT * FROM table2 ORDER BY col");
        SetOperationList unionQueries = (SetOperationList) unionQuery.getSelectBody();
        System.out.println(unionQueries.getOrderByElements());
        unionQueries.getSelects().forEach(query -> {
            PlainSelect plainQuery = (PlainSelect) query;
            System.out.println(plainQuery.getOrderByElements());
        });

3. Actual Output:

null
null
[col]

Expected behavior
The expected output is as follows:

[col]
null
null

Ref

• PostgreSQL: Re: ORDER BY with UNION
• sql - How to order by with union - Stack Overflow

System

• Database you are using: PostgreSQL
• Java Version: 11.0.3
• JSqlParser version: 3.1