From: rich gray
Date: October 4 2012 2:01pm
Subject: Re: (real) silly question about variables...
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On 04/10/2012 15:52, MAS! wrote:
> Hi
>
> I know there'd be a reason, but I can't understand that..
>
> mysql> select @valore:=rand(), @valore, @valore:="ciao", @valore;
> +-------------------+-------------------+-----------------+---------+
> | @valore:=rand()   | @valore           | @valore:="ciao" | @valore |
> +-------------------+-------------------+-----------------+---------+
> | 0.483624490428366 | 0.483624490428366 | ciao            |       0 |
> +-------------------+-------------------+-----------------+---------+
> 1 row in set (0.00 sec)
>
> mysql> select @valore:=rand(), @valore, @valore:="ciao", @valore;
> +-------------------+-------------------+-----------------+---------+
> | @valore:=rand()   | @valore           | @valore:="ciao" | @valore |
> +-------------------+-------------------+-----------------+---------+
> | 0.747058809499311 | 0.747058809499311 | ciao            | ciao    |
> +-------------------+-------------------+-----------------+---------+
> 1 row in set (0.00 sec)
>
> why in the first execution the latest value is 0 and not 'ciao'?
> and why in the first 2 columns the variables seems works as expected!?
what version of MySQL are you running? I get this:-

Server version: 5.5.17-log MySQL Community Server (GPL)

mysql>  select @valore:=rand(), @valore, @valore:="ciao", @valore;
+--------------------+--------------------+-----------------+---------+
| @valore:=rand()    | @valore            | @valore:="ciao" | @valore |
+--------------------+--------------------+-----------------+---------+
| 0.8187706152151997 | 0.8187706152151997 | ciao            | ciao    |
+--------------------+--------------------+-----------------+---------+

Rich