则执行相应的 statement(s)。如果 condition 为假，则跳过该条件并检查下一个 ELSE IF 条件，如果没有...
[ELSE statement_list] END IF 与PHP中的IF语句类似,当IF中条件search_condition成立时,执行THEN后的statement_list语句,否则判断ELSEIF中的条件,成立则执行其后的statement_list语句,否则继续判断其他分支。当所有分支的条件均不成立时,执行ELSE分支。search_condition是一个条件表达式,可以由“=、<、<=、>、>=、!
CREATE PROCEDURE cusBycon AS IF (SELECT COUNT(*) FROM Customers WHERE Country = "France") == 0 BEGIN IF (SELECT COUNT(*) FROM Customers WHERE Country = "Germany") = 0 BEGIN SELECT * FROM Customers WHERE Country = "Australia" as Country END ELSE BEGIN SELECT * FROM Customers WHERE Coun...
1. IF-ELSE语句的语法 在MySQL中,IF-ELSE语句的基本语法如下所示: IF condition THEN statement1; statement2; ... ELSE statement3; statement4; ... END IF; 1. 2. 3. 4. 5. 6. 7. 8. 9. 其中,condition是一个布尔表达式,如果为真(即非零),则执行statement1,statement2等等;如果为假(即零),...
select * from authors where au_id like ' 2* ' end begin select cust_id,cust_name from custom order by cust_id end IF...ELSE语句 语法 IF Boolean_expression {sql_statement|statement_block} else {sql_statement|statement_block} 如果要执行的T-SQL语句不只一行时,就必须要使用BEGIN...END语句...
A case statement must result in a value, not an expression. So this won't work: select case when 1=1 then 1 in (1,2,3) end But this will work; select case when 1=1 then 1 end The value can be the result of a subquery. So one solution would be to rewrite the where clau...
You can use theCASEstatement within theWHEREclause.
BY FIELD，还有其他区别。我不确定我是否会这样做。我想我会使用一个子查询，类似于：
Can I UPDATE, then INSERT if no record updated? Can I use a COLLATE clause in a temp table definition? Can I use aggregate function within CASE? Can I use if statement in a table valued function? Can I use LEN or DATALENGTH in a WHERE clause? Can I use OUTER JOIN on 2 columns at...
CASE WHEN Statement Extract Data From Date — Time Columns SELF JOIN 注意:我使用的是SQLite DB浏览器和在Faker上自行创建的Dummy_Sales_Data,你可以在我的Github存储库上免费获得它! Common Table Expressions (CTE) 在处理现实生活中的数据时,有时需要查询另一个查询的结果。实现此目的的一种简单方法是使用子...