group by / having

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От Alain TESIO
Тема group by / having
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Msg-id 00cb01bf4a3a$c6046a80$f15f72c3@atesio
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Ответы Re: [SQL] group by / having  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-sql
Hello,

Do you know why this command doesn't work ?

> select * from T;
x|y
-+-
1|1
1|2
2|1
2|2
2|3

> select X,Y from T group by X having Y=min(Y);

ERROR:  Illegal use of aggregates or non-group column in target list


My goal is quite simple : get only one line per X value (the value which is
returned for Y is not important as long as it's one of the values linked to
the right X).

The query "select X,Y from T group by X" works under MySQL and
returns exactly what I want, how can I do it in PostgreSQL ?

Thanks for your help,
Alain




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