About me:Oracle ACE pro,optimistic,passionate and harmonious. Focus on ORACLE,MySQL and other database programming,peformance tuning,db design, j2ee,Linux/AIX,Architecture tech,etc
全部博文(191)
发布时间:2026-03-30 17:44:51
ORACLE和MySQL的hash join,如果hash table返回0行,则probe table不需要执行,执行次数是0,而PG的还会执行,hash table a返回0行,但是probe table b还要执行,只不过最多只扫描满足条件的一行去探测,发现hash table没有数据,后面的不再探测
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发布时间:2026-03-30 14:27:55
oracle的外连接where内表过滤条件是函数,包括自定义函数,没有其他额外非函数的过滤条件,则不能转为inner join,只能走外连接,然后外层FILTER过滤where条件,一般来说,效率比inner join低,增加 内表条件 is not null 则可以转为inner join,数学运算可以转为inner join......【阅读全文】
吻的感觉适2025-07-18 23:11
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