Paul Halliday Why does a group_concat on a join change aggregate values?
May 07, 2015; 11:17
Paul Halliday
Why does a group_concat on a join change aggregate values?
Fighting a bit with this one...
If I do something like (pseudo):
SELECT count(val) AS n, GROUP_CONCAT(types) AS c_types FROM tbl1
returns something like:
n c_types 1 t9
when I add a left join though:
SELECT count(val) AS n, GROUP_CONCAT(types) AS c_types, GROUP_CONCAT(two.types) AS d_types FROM tbl1 LEFT JOIN tbl2 AS two ON tbl1.id = tbl2.id
returns something like:
val c_types d_types 3 t9,t9,t9 a2,a3,a9
I can have as many group_concats against the same table with varying results and they don't affect COUNT() but once I do that JOIN things start to fall apart.
What is happening behind the scenes?
Thanks!
-- Paul Halliday http://www.pintumbler.org/
May 07
shawn l.green Re: Why does a group_concat on a join change aggregate values?
May 07, 2015; 15:11
shawn l.green
Re: Why does a group_concat on a join change aggregate values?
May 07
Bob Eby Re: Why does a group_concat on a join change aggregate values?
May 07, 2015; 17:01
Bob Eby
Re: Why does a group_concat on a join change aggregate values?
May 07
Paul Halliday Re: Why does a group_concat on a join change aggregate values?
May 07, 2015; 20:42
Paul Halliday
Re: Why does a group_concat on a join change aggregate values?
May 09
hsv Re: Why does a group_concat on a join change aggregate values?
May 09, 2015; 08:01
hsv
Re: Why does a group_concat on a join change aggregate values?
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