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Comments - GROUP BY

5 months, 2 weeks ago keke magdales
Re: GROUP BY

Hi,

I notice I got a different result between those two request :

A°/ SELECT wins, COUNT(*) FROM plays GROUP BY wins; B°/ SELECT wins, COUNT(*) FROM plays GROUP BY 'wins';

On A°/ i got the normal result : +------+----------+

winsCOUNT(*)

+------+----------+

31
51
82

+------+----------+

As for B° I got something strange : +------+----------+

winsCOUNT(*)

+------+----------+

54

+------+----------+

Could someone tell me the reason ?

Many thanks !

 
5 months, 2 weeks ago Ian Gilfillan
Re: GROUP BY

Because 'wins' in single quotes doesn't exist, so the latter query is essentially the same as 

SELECT wins, COUNT(*) FROM plays GROUP BY NULL;
+------+----------+
| wins | COUNT(*) |
+------+----------+
|    5 |        4 |
+------+----------+

You may have been trying to use backticks (see Identifier Names):

SELECT wins, COUNT(*) FROM plays GROUP BY `wins`;
+------+----------+
| wins | COUNT(*) |
+------+----------+
|    3 |        1 |
|    5 |        1 |
|    8 |        2 |
+------+----------+
 
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