Question

I work with MySQL 5.5. I have a table comment.
When I make this query:

 select sum(case when comment.entity_id=1 and comment.entity_type=1 then 1 else 0 end) as result1;

I get

ERROR 1109 (42S02): Unknown table 'comment' in field list

This should not happen, since

select * from comment;

works just fine.

Where is the error?

Answer 1

You are missing a FROM clause:

SELECT SUM(CASE WHEN entity_id = 1 AND entity_type = 1 THEN 1 ELSE 0 END) AS result1
FROM comment