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From: | Konstantin Osipov | Date: | January 21 2009 11:04pm |

Subject: | Re: Optimization of repeated expressions | ||

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* Baron Schwartz <baron@stripped> [09/01/14 04:41]: > A friend asked me this question, and I thought I should ask it here > before I try to figure it out on my own: > > select id, pow(sum(x),4) + pow(sum(x),3) + > pow(sum(x),2) + sum(x) as z > from foo > group by id > > Would mysql have to compute sum(x) four times, or is it smart enough to > do it once then use the result four times? The sum will be computed 4 times. You should use an alias instead. --

Thread | ||
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• Optimization of repeated expressions | Baron Schwartz | 14 Jan |

• Re: Optimization of repeated expressions | Konstantin Osipov | 22 Jan |