mysql - 一句SQL, 该怎么优化-PHP中文网问答

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mysql - 一句SQL, 该怎么优化

黄舟 2017-04-17 11:26:03

[MySQL讨论组]

337

SELECT 
  (SELECT 
    MAX(`word_id`) 
  FROM
    `tbl_user_words` 
  WHERE `member_id` = 1) AS max_id,
  (SELECT 
    COUNT(`word_id`) 
  FROM
    `tbl_user_words` 
  WHERE `right_count` < 5 
    AND `member_id` = 1) AS num ;

看起来怪怪的～

黄舟

人生最曼妙的风景，竟是内心的淡定与从容！

全部回复(4)

PHP中文网2017-04-17 11:28:03 4楼

试试这条语句, 帅气不?

SELECT MAX(`word_id`) AS max_id, SUM(`right_count` < 5) as num
FROM `tbl_user_words` 
WHERE `member_id` = 1;

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伊谢尔伦2017-04-17 11:28:03 3楼

请将所有语句分开到代码中操作。。。。你看着不头痛么

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伊谢尔伦2017-04-17 11:28:03 2楼

select max(t1.word_id) as max_id, count(t2.word_id) as num from tbl_user_words as t1, tbl_user_words as t2 where t1.member_id = 1 and t2.member_id = 1 and t2.right_count < 5

这样写可能清晰点。

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