Query_to_xml 结果为空

Question

I have the following problem and I hope you can help me:

If I run the following query on my postgresDB, I get a resultset where the id is '123'

SELECT * 
FROM public.table 
WHERE public.table.id = '123';

But I need to get the result in XML format. So I run the following query

SELECT query_to_xml('SELECT * from public.table WHERE public.table.id = CAST(123 as varchar)', TRUE, FALSE, '');

Unfortunately I get an empty table as a result. I don't understand the difference between the 2 queries.

Result:

 <table xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

 </table>

Note: The column 'id' is of type varchar in my case.

I'm not a native English speaker, so sorry for grammar mistakes. I'm also new to databases. So I hope it's not a stupid question.

Thank you for your assistance.

Answer 1

as per comments the problem may arise because the data casting, to keep the query comparing without casting, the solution is to escape the quotes with two single quotes:

SELECT query_to_xml('SELECT * from public.table WHERE public.table.id = ''123''', TRUE, FALSE, '');