2)如果都没匹配,而且没有ELSE语句就返回NULL值。 2.举例: SELECTOrderID, Quantity,CASEWHENQuantity>30THEN'The quantity is greater than 30'WHENQuantity=30THEN'The quantity is 30'ELSE'The quantity is under 30'ENDASQuantityTextFROMOrderDetails; SELECTCustomerName, City, CountryFROMCustomersORDERBY(CASE...
We can have multiple conditions in a Case statement; however, it works in a sequential model. If one condition is satisfied, it stops checking further conditions We cannot use a Case statement for checking NULL values in a table Conclusion The Case statement in SQL provides flexibility in ...
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
CASE 语句也是用来进行条件判断的,它提供了多个条件进行选择,可以实现比 IF 语句更复杂的条件判断。CASE 语句的基本形式如下: CASE case_value WHEN when_value THEN statement_list [WHEN when_value THEN statement_list]... [ELSE statement_list] END CASE 情况1:类似于java中的switch语句,一般用于实现的等值...
sql_statement_recompile扩展事件 (XEvent) 报告语句级重新编译。 当任何类型的批处理需要语句级重新编译时,会发生此 XEvent。 这包括存储过程、触发器、即席批处理和查询。 可通过几个接口来提交批处理,这类接口包括 sp_executesql、动态 SQL、“准备”方法或“执行”方法。
CASE WHEN is like an IF statement in a programming language. It is useful when we need to calculate a statistic on a certain subset of the data. In the image above, I calculate an average price for products sold in the US. I wasn’t careful with the ELSE in the CASE WHEN. ...
SELECT contact_id, CASE WHEN website_id = 1 THEN 'TechOnTheNet.com' WHEN website_id = 2 THEN 'CheckYourMath.com' END With the ELSE clause omitted, if no condition was found to be true, the CASE statement would return NULL.
7 Muffy 24 Indore 10000.00 NULLAdvertisement - This is a modal window. No compatible source was found for this media.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.Exam...
SQL CASE 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'...
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...