sql case statement
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,
PL/SQL also has CASE expression which is similar to the CASE statement. A CASE expression evaluates a list of conditions and returns one of multiple possible result expressions. The result of a CASE expression is a single value whereas the result of a CASE statement is the execution of a se...
The SQLCASEstatement evaluates a list of conditions and adds a column with values based on the condition. For example, -- add a new column 'order_volume' in the Orders table-- and flag any order greater than 10000 as 'Large Order'-- and smaller than 10000 as 'Small Order'SELECT*,CASE...
CASE Statement with ORDER BY ClauseWe can use CASE statement with ORDER BY clause. The ORDER BY clause in SQL sorts the result in ascending (default) or descending order.ExampleIn this query, the CASE statement is used to sort the results based on either the 'NAME' column or the '...
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。) ...
This Oracle tutorial explains how to use the Oracle / PLSQL CASE statement with syntax and examples. 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
TheCASE expressionis used to build IF … THEN … ELSE statements into your Microsoft SQL Server T-SQL code. CASE is used within a SQL statement, such as SELECT or UPDATE. Don’t mistake CASE for theIF ELSEcontrol of flow construct, which is used to evaluate the conditional execution of ...
CASE @Gender WHEN 0 THEN 'M' WHEN 1 THEN 'F' end, @Statecode, @salary) In the following screenshot, we can see the newly inserted row contains Gender M instead of value 0. Case Statement limitations We cannot control the execution flow of stored procedures, functions using a Case st...
Performance optimization: by reducing the complexity of the SQL queries, the CASE statement can also contribute to optimizing the performance and minimize the execution time, especially when it avoids the need for additional computations and transformations. ...