Transact-SQL
Transact-SQL语言是SQL语言的增强版
声明局部变量
DECLARE {@变量名称[AS]变量类型}
注释方式
单行注释：–
多行注释：/* … */
流程控制语句
IF…ELSE语句
IF 表达式 {语句块} ELSE {语句块}
语句块中包含BEGIN…end语句
CASE语句
CASE 表达式 WHEN...THEN... [n...] [else] end
Select 员工姓名，所任职位，员工职称
Case 所任职位
when ‘经理’ then ‘高级职称’
when ‘主管’ then ‘中级职称’
else ‘其他职称’
end
FROM 员工信息
while语句
while 布尔表达式 {语句块} [BREAK] {语句块} [CONTINUE] 语句块
DECLARE @i int, @num int
Set @i = 1
Set @num = 1
While @i<=10
BEGIN
SET@num=@num*@i
set@i=@i+1
END
PRINT @num
WAITFOR延迟语句
waitfor { DELAY time | TIME time }
Waitfor delay ’00:00:05’
Exec sp_help
Waitfor time ’21:11:05’
Exac sp_helpdb
GOTO语句
Declare @count int Set @counter = 1 While @counter <10 BEGIN Print @counter Set @counter =@counter + 1 If @counter=4 GOTO branch one –jumps to the first branch. If @counter=5 GOTO branch_two –this will never execute. End Branch one: Print ‘jumping to branch one.’ GOTO Branch_three: --this will prevent branch_two from executing Branch two: Print ‘jumping to branch two.’ Branch_three: Print ‘jumping to branch three.’
**TRY…CATCH错误处理语句
begin try {语句块} FND TRY BEGIN CATCH {语句块} end CATCH
Begin try
Declare @num int
Set @num = 1/0
Select @num
End try
Begin catch
Select err_line() as ‘错误行数’
End catch
