SQL 条件语句 (IF, CASE WHEN, IFNULL) 1、IF 1.1 表达式: IF( expr1 , expr2 , expr3 ) expr1条件,条件为true,则值是expr2 ,false,值就是expr3 示例; SELECT o.id,u.account,catagory
问使用CASE和IN更新- OracleEN我编写了一个在SQL Server中非常出色的查询。不幸的是，它需要在Oracle数据...
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。) CASE表达式的用途: 1,转换...
CASE WHEN condition1 THEN result1 [WHEN condition2 THEN result2] ... [ELSE result] END 相关优势 灵活性:可以在查询中直接进行条件判断,而不需要编写额外的程序逻辑。 可读性:通过CASE WHEN可以使 SQL 查询更加直观和易读。 性能:相对于子查询或连接操作,CASE WHEN通常具有更好的性能。
WHEN Salary >=50000 AND Salary <80000 THEN 'Senior Consultant' Else 'Director' END We have following output of this query. In this output, we get minimum and maximum salary for a particular designation. Update statement with a CASE statement We can use a Case statement in SQL with update...
How do you USE CASE statement in MySQL? What is the use of CASE operator in MySQL? What is the case-switch statement in SQL? How to use a case-when statement in a mysql stored procedure? Question: To automatically set the session_id with the request_time parameter, I chose to use a...
以下是具有含簡式 case-statement-when-clause 之 CASE 陳述式的 SQL 程序範例: CREATE PROCEDURE UPDATE_DEPT (IN p_workdept) LANGUAGE SQL BEGIN DECLARE v_workdept CHAR(3); SET v_workdept = p_workdept; CASE v_workdept WHEN 'A00' THEN UPDATE department SET deptname = 'D1'; WHEN 'B01'...
In the T-SQL scripting language, you can use the SQL CASE statement to evaluate a condition and return one or more result expressions. This SQL Tutorial will teach you when and how you can use CASE in T-SQL statements. Solution TheCASE expressionis used to build IF … THEN … ELSE stat...
SQL CASE Statement - Learn how to use the SQL CASE statement to perform conditional logic in your SQL queries effectively.
The syntax for the CASE statement in SQL Server (Transact-SQL) is: CASE expression WHEN value_1 THEN result_1 WHEN value_2 THEN result_2 ... WHEN value_n THEN result_n ELSE result END OR CASE WHEN condition_1 THEN result_1 WHEN condition_2 THEN result_2 ... WHEN condition_n THEN...