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manish007
Starting Member
1 Post |
 Posted - 2004-05-08 : 05:12:05
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| what is difference between these two ???if count (1) is the primary key then count(100) will also return value Why ?????Manish |
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ditch
Master Smack Fu Yak Hacker
1466 Posts |
Posted - 2004-05-09 : 07:43:26
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| count(1) and count(100) will always return the same value - this basically returns the count of all rows in the table which meet whatever criteria has been specified in your where or join filters - ie exactly what count(*) does.count all and count distinct have different functionality though.This is from books online:COUNT(*) returns the number of items in a group, including NULL values and duplicates.COUNT(ALL expression) evaluates expression for each row in a group and returns the number of nonnull values.COUNT(DISTINCT expression) evaluates expression for each row in a group and returns the number of unique, nonnull values.a lot more can be learned from books online about count and other aggregation.the best way to understand it better is to experiment with it.Duane. |
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count(*) and count(1)