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Mysql SQL查询无法正常工作_Mysql_Sql_Database - Fatal编程技术网

Mysql SQL查询无法正常工作

Mysql SQL查询无法正常工作,mysql,sql,database,Mysql,Sql,Database,我有一个基本的数据库,有几列我将在下面向你展示 我有一个程序,允许用户输入他们是男性还是女性,如果他们想输入,则输入NULL 然后,他们必须选择一个类别,如爱情或烹饪 我尝试了这个查询,但没有成功。它显示了其他性别,忽略了Where-Gender=M语句 它只能是一种性别,但可以是不同类型的类别 任何帮助都将不胜感激 SELECT * FROM products WHERE Gender = "M" AND Category = "Love" OR Category = "Cooking"

我有一个基本的数据库,有几列我将在下面向你展示

我有一个程序,允许用户输入他们是男性还是女性,如果他们想输入,则输入NULL

然后,他们必须选择一个类别,如爱情或烹饪

我尝试了这个查询,但没有成功。它显示了其他性别,忽略了Where-Gender=M语句

它只能是一种性别,但可以是不同类型的类别

任何帮助都将不胜感激

SELECT *
FROM products
WHERE Gender = "M"
AND Category = "Love"
OR Category =  "Cooking"
数据库

Id Name Gender Category 
1   AB    M      Love
2   AC    F      Love
3   AS    M      Cooking
4   SF    Null   Cooking 

您需要在OR的周围添加括号

差不多

SELECT *
FROM products
WHERE Gender = "M"
AND (Category = "Love"
OR Category =  "Cooking")
按照你的方式,它将与

SELECT *
FROM products
WHERE (Gender = "M"
AND Category = "Love")
OR Category =  "Cooking"

查看一下

您需要在或周围添加括号

差不多

SELECT *
FROM products
WHERE Gender = "M"
AND (Category = "Love"
OR Category =  "Cooking")
按照你的方式,它将与

SELECT *
FROM products
WHERE (Gender = "M"
AND Category = "Love")
OR Category =  "Cooking"

查看一下

您需要在或周围添加括号

差不多

SELECT *
FROM products
WHERE Gender = "M"
AND (Category = "Love"
OR Category =  "Cooking")
按照你的方式,它将与

SELECT *
FROM products
WHERE (Gender = "M"
AND Category = "Love")
OR Category =  "Cooking"

查看一下

您需要在或周围添加括号

差不多

SELECT *
FROM products
WHERE Gender = "M"
AND (Category = "Love"
OR Category =  "Cooking")
按照你的方式,它将与

SELECT *
FROM products
WHERE (Gender = "M"
AND Category = "Love")
OR Category =  "Cooking"

看一看

为了告诉查询性别必须是“M”,您必须将类别括在括号中:


为了告诉查询性别必须为“M”,您必须将类别括在括号中:


为了告诉查询性别必须为“M”,您必须将类别括在括号中:


为了告诉查询性别必须为“M”,您必须将类别括在括号中:


我认为您需要在此处使用IN运算符,请尝试以下操作:

SELECT *
FROM products
WHERE Gender = 'M'
AND Category IN ('Love','Cooking')

我认为您需要在此处使用IN运算符,请尝试以下操作:

SELECT *
FROM products
WHERE Gender = 'M'
AND Category IN ('Love','Cooking')

我认为您需要在此处使用IN运算符,请尝试以下操作:

SELECT *
FROM products
WHERE Gender = 'M'
AND Category IN ('Love','Cooking')

我认为您需要在此处使用IN运算符,请尝试以下操作:

SELECT *
FROM products
WHERE Gender = 'M'
AND Category IN ('Love','Cooking')

尝试使用单引号:
Gender='M'
尝试使用单引号:
Gender='M'
尝试使用单引号:
Gender='M'
尝试使用单引号:
Gender='M'