fetching records with column value constraints
I have a table like,
Name Privilege
x 1
y 2
x 3
A 1
Now I want to fetch only the names who has a Privilege 1 alone. ie., the reuslt should be,
Name Privilege 开发者_如何学Go
A 1
Can someone help me on this?
SELECT
*
FROM
<table> t
LEFT JOIN
<table> t2
ON
t.Name = t2.Name and
t2.Privilege <> 1
WHERE
t2.Name is null and
t.Privilige = 1
Or you can alternatively write this as a NOT EXISTS clause and a correlated subquery.
Edit
From comment, where you're wanting to find "matches this set, and only this set" - put your conditions in another table (possibly a temp table or table variable), and then start looking at "relational division". A google search on this term brings up a Joe Celko article which is a decent read. The example under "Exact Division" would be of the sort you're talking about.
;WITH set1 AS (SELECT * FROM Privileges WHERE Privilege IN (1, 3))
SELECT up.UserId
FROM UserPrivileges up
INNER JOIN set1 ON set1.Privilege = set1.Privilege
GROUP BY up.UserId
HAVING COUNT(up.Privilege) = (SELECT COUNT(*) FROM set1);
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