mysql查詢語句優(yōu)化-資料下載頁
2024-10-18 16:42本頁面
【正文】 ant_status as s on = where 38570。 查詢語句優(yōu)化實(shí)例分析（三 表 ） 與上面的 SQL取得的結(jié)果不同 explain select count(*) from contestant_info as i left join (select id from contestant_status where id 38570) as s on =。 如果 contestant_status是 contestant_info的子集， votes是contestant_status的子集，那么優(yōu)化后的 SQL explain select count(id) as `t` from contestant_status where statusamp。3 = 0。 查詢語句優(yōu)化實(shí)例分析（三 表 ） 3. 有時 MySQL選擇的索引是最好的，減少記錄集比去掉 filesort更重要 use nengren。 原始 SQL explain SELECT ,a.* FROM article AS a force index(idx_createtime) INNER JOIN (SELECT m.*, FROM nengren AS m INNER JOIN nengren_point AS n ON = WHERE = 1 AND 4) AS b ON = WHERE = 1 AND = 0 AND = 1 AND = 1 ORDER BY DESC LIMIT 10。 優(yōu)化后 explain SELECT , FROM article AS a INNER JOIN nengren as m on = inner join nengren_point as n on = WHERE = 1 AND = 0 AND = 1 AND = 1 and = 1 AND 4 ORDER BY DESC LIMIT 10。 相關(guān)鏈接 ? 整理表的一些語句 Thanks!
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