Använd query analyzer, om du har SQL Server installerat.
Frågan#1
Hej
Dessa två SQL-satser ger identiskt resultat. Men vilken är snabbast. Kan man mäta det på något enkelt sätt?
1
SELECT c.courseID, c.courseName
FROM classParticipants AS ClP INNER JOIN
courseParticipants AS cp ON ClP.UserID = cp.UserID INNER JOIN
courses AS c ON cp.courseID = c.courseID
WHERE (ClP.classID = 58) AND (c.courseEndDate >= GETDATE()) AND (c.courseStartDate <= GETDATE()) AND (cp.courseTeacher = 0)
GROUP BY c.courseID, c.courseName
ORDER BY c.courseName
2
SELECT courseID, courseName
FROM courses AS c
WHERE (courseID IN
(SELECT courseID
FROM courseParticipants AS cp
WHERE (UserID IN
(SELECT UserID
FROM classParticipants AS clp
WHERE (classID = 58))) AND (courseTeacher = 0)))