Mysql case when 多个条件 then讲解
Web3 人 赞同了该文章. case when 的语法有如下两种:. 1 CASE WHEN [expr] THEN [result1]…. ELSE [default] END 2 CASE [col_name] WHEN [value1/expr1] THEN [result1]…. ELSE … WebThe CASE statement goes through conditions and return a value when the first condition is met (like an IF-THEN-ELSE statement). So, once a condition is true, it will stop reading and return the result. If no conditions are true, it will return the value in the ELSE clause. If there is no ELSE part and no conditions are true, it returns NULL.
Mysql case when 多个条件 then讲解
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WebSep 15, 2024 · CASE的简单函数使用简便,但无法应对较为复杂的场景,这就需要用到条件表达式了,其语法结构如下:. CASE WHEN condition THEN result1 ELSE result2 END. … WebFeb 22, 2024 · 本文实例讲述了mysql存储过程之case语句用法。分享给大家供大家参考,具体如下: 除了if语句,mysql提供了一个替代的条件语句CASE。mysql的 CASE语句使代码更加可读和高效。废话不多说,我们先 …
WebJun 26, 2024 · 当两种选择是可以使用if,有多种选择的时候就需要case语句了. 比如在上例子中,我们存储了一些不希望暴露性别的用户,存储的值为3.此时想要查询可以: select s.name '姓名', case s.sex when 1 then '男' when 0 then '女' else '保密' end '性别' from student s. 结果: WebOct 6, 2012 · If id is sequential starting at 1, the simplest (and quickest) would be: UPDATE `table` SET uid = ELT (id, 2952, 4925, 1592) WHERE id IN (1,2,3) As ELT () returns the Nth element of the list of strings: str1 if N = 1, str2 if N = 2, and so on. Returns NULL if N is less than 1 or greater than the number of arguments.
WebAug 15, 2024 · SQL进阶-1-case使用. 认真把SQL语言提升下,选择了日本的一本书籍。看过几本其他日本的IT人员写的书籍,发现他们好像有一个共同的特点,也是自己很喜欢而且一直坚持在使用的一点:多用图,... WebMay 11, 2024 · mysql case when 多参数条件语法。下面的 sql 语句是要将 status 列根据一个条件或者多条件转换为对应的值. 其中要注意 case 关键字后面不能带上列名 status 而是 …
WebOct 25, 2024 · 1.case when then 看下面这个语句大家应该懂 case sex when ‘1’ then ‘男’ when ‘2’ then '女’ else ‘其他’ end –case搜索函数 case when sex = ‘1’ then ‘男’ when sex = ‘2’ then ‘女’ else ‘其他’ end 2.sql聚集函数 在网上找了大概有五种 Max ... sharp tv register warrantyWebMay 9, 2024 · when city_code = 001373 then 1. when city_code = 001957 then 1. when city_code = 002000 then 1. when city_code = 002293 then 1. end) where city_code in … porsche boxster diecast modelWebThe MySQL CASE Statement. The CASE statement goes through conditions and returns a value when the first condition is met (like an if-then-else statement). So, once a condition is true, it will stop reading and return the result. If no conditions are true, it returns the value in the ELSE clause. If there is no ELSE part and no conditions are ... porsche boxster flywheelWebJul 9, 2024 · 参数: input_expression是使用简单 CASE 格式时所计算的表达式,是任何有效的SQL表达式。. when when_expression使用简单 CASE 格式时 input_expression 所比较的简单表达式。when_expression 是任意有效的SQL表达式。input_expression 和每个 when_expression 的数据类型必须相同,或者是隐性转换。 porsche boxster for sale 2013WebTHEN CASE WHEN salary > 1000. THEN 1 ELSE 0 END. ELSE 1 END = 1 ) 如果单纯使用Check,如下所示. CONSTRAINT check_salary CHECK. ( sex = '2' AND salary > 1000 ) 女职员的条件倒是符合了,男职员就无法输入了。. Select top 100 State,JoinState, (case when State=1 and Joinstate=0 then 2 when State=1 and JoinState=1 then 1 ... porsche boxster for sale by owner near meWebThe CASE statement cannot have an ELSE NULL clause, and it is terminated with END CASE instead of END . For the first syntax, case_value is an expression. This value is compared to the when_value expression in each WHEN clause until one of them is equal. When an equal when_value is found, the corresponding THEN clause statement_list executes. porsche boxster for sale aaWebHere is a demo query, notice it is very simple, Fetches only where base_price is 0, And still, it chooses the condition 3: SELECT CASE course_enrollment_settings.base_price WHEN course_enrollment_settings.base_price = 0 THEN 1 WHEN course_enrollment_settings.base_price<101 THEN 2 WHEN … porsche boxster for sale az