mysql-为什么sql查询选择不必要的值？

我想选择条件为true的行。我有一个名为

command

的列，如果列值包含（由我定义的）字符串，则添加到结果

我的问题是选择行，因为查询没有看到WHERE语句，如果列

命令

包含字符串，它会选择所有数据

SELECT * 
FROM `admin_log` 
WHERE `admin_log`.`user` = 'Admin' 
    AND command LIKE '%aznot%' 
    OR command LIKE '%hango%' 
ORDER BY `order_id` DESC 
LIMIT 0, 50

例如，我有3个管理员帐户：Admin、Zuppa、Grund。如果命令列包含：aznot或hango，我想按帐户管理员选择所有数据

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我做错了什么？

你需要一些括号

SELECT * 
FROM `admin_log`
WHERE `admin_log`.`user` = 'Admin'  
AND (command LIKE '%aznot%' OR command LIKE '%hango%')
ORDER BY `order_id` 
DESC LIMIT 0, 50

---

试着这样做：

SELECT * FROM `admin_log` WHERE `admin_log`.`user` = 'Admin' AND (command LIKE '%aznot%' OR command LIKE '%hango%') ORDER BY `order_id` DESC LIMIT 0, 50

SELECT * FROM `admin_log` WHERE `admin_log`.`user` = 'Admin' AND (command LIKE '%aznot%' OR command LIKE '%hango%') ORDER BY `order_id` DESC LIMIT 0, 50

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最好将OR语句分离成单独的表达式，以防止引擎误解

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您需要正确嵌套条件。请参阅SQL中逻辑运算符的优先级规则，查询返回的是什么。您得到的是什么样的结果？

SELECT * FROM `admin_log` WHERE `admin_log`.`user` = 'Admin' AND (command LIKE '%aznot%' OR command LIKE '%hango%') ORDER BY `order_id` DESC LIMIT 0, 50

SELECT * 
FROM   `admin_log` 
WHERE  `admin_log`.`user` = 'Admin' 
       AND (command LIKE '%aznot%'
        OR command LIKE '%hango%' )
ORDER  BY `order_id` DESC 
LIMIT  0, 50