利用分析函数优化自连接
摘要:春节回来上班第一天也够蛋疼的,盖儿又给我发了一个SQL,他说这个SQL db file sequential read 很高,要跑120秒,逻辑读有1626677 叫我帮忙优化一下,SQL语句如下: select distinct decode(length(a.category_id), ...
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posted @ 2012-01-30 16:34
posted @ 2012-01-30 16:34
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