sql case statement
CASE 语句在指定的搜索条件为 true 时执行一条或多条语句。 CASE 是独立的语句,它与必须作为表达式组成部分出现的 CASE 表达式不同。 CASE 语句有两种形式:简单 CASE 语句和搜索型 CASE 语句。 简单CASE 语句 (PL/SQL) 简单CASE 语句尝试将表达式 (称为选择器) 与一个或多个 WHEN 子句中指定的另一个表达式...
1.CASE 写法如下: CASE WHEN condition1 THEN result1 WHEN condition2 THEN result2 WHEN conditionN THEN resultN ELSE result END; 解释:1)先匹配第一条,不匹配的话继续第二条,如此循环,
Oracle / PLSQL:CASE Statement This Oracle tutorial explains how to use the Oracle/PLSQLCASE statementwith syntax and examples. Description The Oracle/PLSQL CASE statement has the functionality of an IF-THEN-ELSE statement. Starting in Oracle 9i, you can use the CASE statement within a SQL sta...
CASE With ELSE ACASEstatement can have an optionalELSEclause. TheELSEclause is executed if none of the conditions in theCASEstatement is matched. Syntax SELECTcustomer_id, first_name,CASEWHENcondition1THENresult1WHENcondition2THENresult2-- Add more WHEN conditions and results as neededELSEelse_resu...
WHEN 1 THEN'Salaried Employee'WHEN 0 THEN'Contractor'ELSE'N/A'END FROM [HumanResources].[Employee] The downside of the simple CASE statement is that you can only check for equality. The IIF function With SQL Server 2012, theIIF functionwas introduced into the T-SQL language. The syntax is...
SQL CASE Statement - Learn how to use the SQL CASE statement to perform conditional logic in your SQL queries effectively.
We have following syntax for a case statement in SQL with a simple expression 1 2 3 4 5 6 SELECT CASE Expression When expression1 Then Result1 When expression2 Then Result2 ... ELSE Result END Usually, we store abbreviations in a table instead of its full form. For example, in my...
CASE表达式是用来判断条件的,条件成立时返回某个值,条件不成立时返回另一个值。 语法: CASEWHENComparsionConditionTHENresultWHENComparsionConditionTHENresultELSEotherEND (注:各分支返回的数据类型需一致。) (注:when子句一定要有排他性,因为当when子句为真时,剩余的when子句会被忽略。) ...
目前流行的ORM框架如果需要动态的拼接查询语句,只能用原生的sql进行拼接,无法跨不同数据库执行。hisql推出新的语法一套语句可以在不同的数据库执行 传统ORM框架最大的弊端就是完全要依赖于实体用lambda表达式写查询语句,但最大的问题就是如果业务场景需要动态拼接条件时只能又切换到原生数据库的sql语句进行完成,如果自行...