having

I made a bit of a fool out of myself earlier today on this question . The question was using SQL Server, and the correct answer involved adding a HAVING clause. The initial mistake I made was to think that an alias in the SELECT statement could be used in the HAVING clause, which is not allowed in SQL Server. I made this error because I assumed that SQL Server had the same rules as MySQL, which does allow an alias to be used in the HAVING clause. This got me curious, and I poked around on Stack Overflow and elsewhere, finding a bunch of material explaining why these rules are enforced on the

Say there is such table: mysql> SELECT * FROM tags; +---------+--------+ | post_id | tag_id | +---------+--------+ | 1 | 2 | | 1 | 3 | | 1 | 1 | | 2 | 1 | | 2 | 2 | +---------+--------+ 5 rows in set (0.00 sec) Field names are pretty self-explanatory. I want to select post_id s that have both 1 and 3 tag_id s, so in this example it's only 1 . I thought of something like SELECT post_id FROM tags GROUP BY post_id HAVING ... After having I'd like to list tag_id s that are present in this group. How do I do that? rudi-moore If there aren't any unique constraints try: SELECT post_id FROM tags WHERE

I have following query in PostgreSQL: SELECT COUNT(a.log_id) AS overall_count FROM "Log" as a, "License" as b WHERE a.license_id=7 AND a.license_id=b.license_id AND b.limit_call > overall_count GROUP BY a.license_id; Why do I get this error: ERROR: column "overall_count" does not exist My table structure: License(license_id, license_name, limit_call, create_date, expire_date) Log(log_id, license_id, log, call_date) I want to check if a license has reached the limit for calls in a specific month. SELECT a.license_id, a.limit_call , count(b.license_id) AS overall_count FROM "License" a LEFT JOIN

I often see people answer MySQL questions with queries like this: SELECT DAY(date), other columns FROM table GROUP BY DAY(date); SELECT somecolumn, COUNT(*) FROM table HAVING COUNT(*) > 1; I always like to give the column an alias and refer to that in the GROUP BY or HAVING clause, e.g. SELECT DAY(date) AS day, other columns FROM table GROUP BY day; SELECT somecolumn, COUNT(*) AS c FROM table HAVING c > 1; Is MySQL smart enough to notice that the expressions in the later clauses are the same as in SELECT , and only do it once? I'm not sure how to test this -- EXPLAIN doesn't show any

I am trying to accomplish the following in MySQL (see pseudo code) SELECT DISTINCT gid FROM `gd` WHERE COUNT(*) > 10 ORDER BY lastupdated DESC Is there a way to do this without using a (SELECT...) in the WHERE clause because that would seem like a waste of resources. try this; select gid from `gd` group by gid having count(*) > 10 order by lastupdated desc I'm not sure about what you're trying to do... maybe something like SELECT gid, COUNT(*) AS num FROM gd GROUP BY gid HAVING num > 10 ORDER BY lastupdated DESC SELECT COUNT(*) FROM `gd` GROUP BY gid HAVING COUNT(gid) > 10 ORDER BY lastupdated