Re: Sequential select queries...??
От | Josh Berkus |
---|---|
Тема | Re: Sequential select queries...?? |
Дата | |
Msg-id | web-105146@davinci.ethosmedia.com обсуждение исходный текст |
Ответ на | Sequential select queries...?? (Mark Mikulec <mm98au@badger.ac.brocku.ca>) |
Список | pgsql-sql |
Mark, > What i'd like to do is the following: > > Select id from T where name = 'bleh'; > > and > > Select id from T where description = 'bleh'; > > and result both results in the same result set. That is, duplicate > id's > if they appear. So then I could do a GROUP BY and a COUNT to see how > many appeared in only one, and how many appeared in both. What you want is UNION ALL. You also want to go out and purchase "SQL for Smarties" after you finish reading my e-mail. SELECT id FROM T WHERE name = 'bleh' UNION ALL SELECT id FROM T WHERE description = 'bleh'; This gives you both result sets, once right after the other. If you didn't want to see duplicate values (i.e. only one instance of each "id"), you would use simply UNION without the "ALL". This means that it is possible to get both your desired rowcounts out of a *single* query, using subselects. "SQL for Smarties" can help you learn to build this kind of query. -Josh ______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete informationtechnology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small businesses fax 621-2533 and non-profit organizations. San Francisco
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