Sql的case when then else end

Author: adqq

August undefined, 2024

WebMay 9, 2024 · case when then else end 可以理解为java的if-else if -else。可以理解为流程控制语句或条件控制语句。可以实现资料获取的时候，可以更多的条件和自定义逻辑。1.已 … WebApr 19, 2024 · ELSE and AS are optional. The CASE statement must go in the SELECT clause. SELECT name, CASE WHEN submitted_essay IS TRUE THEN 'essay submitted!' …

case when then else - CSDN文库

WebMar 14, 2024 · case when then else. "case when then else" 是一种 SQL 语句中的条件表达式，用于根据不同的条件返回不同的结果。. 它的语法结构为：. CASE WHEN condition1 THEN result1 WHEN condition2 THEN result2 ELSE result3 END. 其中，condition1 和 condition2 是条件表达式，result1、result2 和 result3 是根据 ... WebMar 31, 2024 · There we have it! For each row where the Price is below 1.00, the string 'Below $1.00' is returned. For Price values greater than or equal to 1.00, the string 'Greater … loans for really poor credit

PostgreSQL CASE Statements & Examples using WHEN-THEN, if-else …

WebFeb 7, 2024 · Using within SQL select. val df4 = df. select ( col ("*"), expr ("case when gender = 'M' then 'Male' " + "when gender = 'F' then 'Female' " + "else 'Unknown' end"). alias ("new_gender")) 3. Using && and operator We can also use and (&&) or ( ) within when function. To explain this I will use a new set of data to make it simple. WebJun 5, 2024 · case when then else end 语句用于查询满足多种条件的情况。主要是两种使用场景：一是类似java中的if…else；二是用于进行行转列的查询（参看以下链接场景3 的例 … WebApr 6, 2024 · id-case when 1 like 1 then 0 else 2*1e308 end. 0x01 测试数据 ... SQL Server注入中的小技巧-开篇 ... loans for really bad credit score number

MySQL中的函数（大数据学习）_Shadow️的博客-CSDN博客

WebApr 14, 2024 · if 函数有三个参数，第一个参数 boolean(布尔类型true false) , 第二个参数和第三个参数都是值，前⾯的条件如果成⽴，取值第⼀个，否则取值第⼆个。顾名思义，就是判断数据是否存在的！exists的作用为判断一个表中的数据，是否在另外的一张表中能够查询到与之对应的数据。 WebJun 18, 2024 · SQL中的case when then else end用法 Case具有两种格式。简单Case函数和Case搜索函数。 --简单Case函数 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 这两种方式，可以实现相同的功能。简单Case函数的写法相对比较简洁，但是 … indianapolis mobility scooter rentalWebApr 11, 2024 · SQL语句中的case when语法以及Oracle中的类似方法. 一、基本概念和例子case when是sql语句的语法，而不是属于特定数据库的语言方法一：select num,name, … indianapolis model car show

"WebNov 4, 2015 · SQL evaluates the case statement first, which will return either a 0 or 1. Then the SUM operation adds up the values. You can make the CASE statement as complex as you need it to be, even looking up data in other tables. Share Improve this answer Follow answered Nov 3, 2015 at 20:21 Jonathan Fite 8,103 1 20 30 " - Sql的case when then else end

Sql的case when then else end

WebMar 13, 2024 · select case when 条件 then 结果1 else 结果2 end 这是一种SQL语句中的条件判断语句，根据条件的真假返回不同的结果。当条件成立时，返回结果1，否则返回结果2 … Websql case 语句. case语句遍历条件并在满足第一个条件时返回一个值（如if-then-else语句）。因此，一旦条件为真，它将停止读取并返回结果。如果没有条件为 true，则返回 else 子 …

Did you know?

Webselect country, sum ( case when sex = '1' then population else 0 end), --男性人口 sum ( case when sex = '2' then population else 0 end) --女性人口 from table_a group by country; 复制 …

WebIn a simple CASE expression, Oracle searches for the first WHEN ... THEN pair for which expr is equal to comparison_expr and returns return_expr. If none of the WHEN ... THEN pairs meet this condition, and an ELSE clause exists, then Oracle returns else_expr. Otherwise, Oracle returns null. WebMysql：使用case when then end 实现行列转换 1、创建一张表，我们这表名为 t_score 2、添加若干条数据 3、用case when then end 函数进行查询效果图：另一种方法获取所需结果利用with rollup 给结果集新添一行，再使用ifnull过程函数判断name的值是否为空 ... Oracle中的case when then else end用法详解目录阐述适用情景举例说明结合其他语言理解小结阐 …

WebConclusion – SQL if then else We can use IF and ELSE keywords in SQL to perform conditional execution of the statements depending on the condition evaluating to a boolean value. Alternatively, we can use the CASE statement to implement if then else functionality in SQL. Recommended Articles WebELSE result_n END Here are some critical points that you should keep in mind while constructing CASE s in PostgreSQL: Each condition is a boolean expression and based on its output the result is chosen. If all the expressions corresponding to WHEN are evaluated to be False, then the result respective to the ELSE part is shown.

WebApr 15, 2024 · SUM( CASE WHEN sex = ‘1’ THEN population ELSE 0 END ), –男性人口 SUM( CASE WHEN sex = ‘2’ THEN population ELSE 0 END ) –女性人口 FROM Table_A GROUP BY country; 得到如下结果：就第一个CASE WHEN讲解： CASE WHEN sex = ‘1’ THEN population ELSE 0 END. 当记录的sex为1时，这个字段的值为记录的 ...

WebJan 25, 2024 · SQL 複製 WITH Data (value) AS ( SELECT 0 UNION ALL SELECT 1 ) SELECT CASE WHEN MIN(value) <= 0 THEN 0 WHEN MAX(1 / value) >= 100 THEN 1 END FROM … indianapolis model train showWebNov 12, 2024 · Yes, you might use CASE… WHEN… ELSE… END in a WHERE clause. SELECT * FROM TABLE_USERS WHERE POINTS = CASE WHEN user = 'test user' THEN '100' ELSE … indianapolis model railroad showWebELSE '其他' END --Case搜索函数 CASE WHEN sex = '1' THEN '男' WHEN sex = '2' THEN '女' ELSE '其他' END 这两种方式，可以实现相同的功能。简单Case函数的写法相对比较简洁，但是和Case搜索函数相比，功能方面会有些限制，比如写判断式。还有一个需要注意的问题，Case函数只返回第一个符合条件的值，剩下的Case部分将会被自动忽略。 --比如说， … loans for rental propertyWebDefinition and Usage The 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 … indianapolis model railroad clubWeb可以的话，留个qq就更好啦~ 贴一段代码看看： case when locate(x'0a', a.main_ph_num)>0 then substr(a.main_ph_num, 1,locate(x'0a',a.main_ph_num)-1) else a.main_ph_num end as acct_tel_no from adbcn.acct_on_page_cn a loans for renewable energy projectsWeb可以的话，留个qq就更好啦~ 贴一段代码看看： case when locate(x'0a', a.main_ph_num)>0 then substr(a.main_ph_num, 1,locate(x'0a',a.main_ph_num)-1) else a.main_ph_num end as … loans for rental assistanceWebApr 11, 2024 · SQL语句中的case when语法以及Oracle中的类似方法. 一、基本概念和例子case when是sql语句的语法，而不是属于特定数据库的语言方法一：select num,name, (case classnowhen '1' then '一班'when '2' then '二班'else '其他班级'end) as classnamefrom student方法二：select num. oracle sql decode case when ... indianapolis monthly jobs