Question

我正在按照所选值执行过滤器，这是我的数据库的样子：

contactgroup  media  gender  age  isdelete  married  children driverslicens restatus retype
        -----------------------------------------------------------
        contactgroup1     SMS        Male     28     0   yes   yes     yes   owner    apart           
        contactgroup1     SMS        Female   26     0   no    null    no     rent  house
        contactgroup2     SMS        Male     32     0   null   no      null    owner  null
        contactgroup2     SMS        Male     38     0   yes    yes     no      null   null

这是我的疑问：

SELECT * FROM contact
  where isdeleted = 0
    AND contactgroup in ('Contactgroup1', '')
    and media = 'sms'
    AND (`gender` = 'female' OR `gender` = 'male' OR `gender` is null)
    AND (`married` = 'yes' OR `married` = 'no' OR `married` is null)
    AND (`children` = 'yes' OR `children` = 'no' OR `children` is null)
    AND (`driverslicense` = 'yes' OR `driverslicense` = 'no' OR `driverslicense` is null)
    AND (`retype` = 'owner' OR `retype` = 'renting' OR `retype` is null)
    AND (`restatus` = 'apart' OR `restatus` = 'house' OR `restatus` is null)
    and age BETWEEN 18 AND 60

此查询应显示有关contactgroup1的数据，但是它显示了所有四个数据，任何人都可以告诉我为什么它显示我出错的所有数据？

Answer 1

您需要整理查询和分组OR条件

SELECT 
  * 
FROM
  contact 
WHERE isdeleted = 0 
  AND contactgroup IN ('Contactgroup1', '') 
  AND media = 'sms' 
  AND (
    `gender` = 'female' 
    OR `gender` = 'male' 
    OR `gender` = 'null'
  ) 
  AND age BETWEEN 18 
  AND 60

Demo

使用新列

更新问题

您需要使用IS NULL

来识别null

SELECT 
  * 
FROM
  contact 
WHERE isdelete = 0 
  AND contactgroup IN ('Contactgroup1', '') 
  AND media = 'sms' 
  AND (
    `gender` = 'female' 
    OR `gender` = 'male' 
    OR `gender` = 'null'
  ) 
  AND (
    `married` = 'yes' 
    OR `married` = 'no' 
    OR `married` IS NULL
  ) 
  AND age BETWEEN 18 
  AND 60

Demo 2

Answer 2

查询中的条件需要在支持中弹出，您需要在搜索中应用一些以上的基本逻辑：

SELECT 
    * 
FROM 
    contact 
where 
    isdeleted = 0 
    AND contactgroup in ('Contactgroup1', '') 
    and media = 'sms' 
    AND
    ( 
        `gender` = 'female' 
        OR `gender` = 'male' 
        OR `gender` = 'null' 
    )
    and age BETWEEN 18 AND 60

任何引入OR语句的where子句基本上都会导致数据库忽略任何其他AND语句并返回任何匹配的数据。

在您的查询中，您有

OR `gender` = 'male' 
OR `gender` = 'null'

这基本上意味着带回与此数据匹配的任何行。查询中的更改现在使得必须满足所有其他AND语句 - 只要在括号内满足OR个语句中的至少一个。

Answer 3

在OR周围使用括号 - 这样的条件：

SELECT 
  *
FROM 
  contact 
WHERE isdeleted = 0
AND contactgroup in ('Contactgroup1', '')
AND media = 'sms' 
AND (gender = 'female' OR gender = 'male' OR gender = 'null')
AND age BETWEEN 18 AND 60

这称为 Operator Precedence - AND比OR更重要，所以如果你不使用括号，就像你这样做：

SELECT 
  *
FROM 
  contact
WHERE (isdeleted = 0 AND contactgroup in ('Contactgroup1', '') and media = 'sms' AND gender = 'female')
OR (gender = 'male')
OR (gender = 'null' AND age BETWEEN 18 AND 60)

MYSQL查询未正确显示数据

3 个答案:

Demo

Demo 2