SQLSERVER中的流程控制语句

DECLARE @i int;
　　SET @i = 1;
　　GO        --分批了
　　PRINT @i  --@i在这个批里未定义

DECLARE @count INT
SELECT @count = 0
WHILE @count < 10
BEGIN
    PRINT 'count = ' + CONVERT(VARCHAR(10), @count)
    SELECT @count = @count + 1
END

PRINT 'loop finished, count = ' + CONVERT(VARCHAR(10), @count)

IF Boolean_expression 
     { sql_statement | statement_block } 
[ ELSE 
     { sql_statement | statement_block } ]

DECLARE @score INT
SET @score = 100
IF @score >= 60
    PRINT '及格'
ELSE
    PRINT '不及格'

CASE input_expression 
     WHEN when_expression THEN result_expression [ ...n ] 
     [ ELSE else_result_expression ] 
END

CASE
     WHEN Boolean_expression THEN result_expression [ ...n ] 
     [ ELSE else_result_expression ] 
END

DECLARE @score INT
SET @score = 100

SELECT CASE @score 
            WHEN 100 THEN '满分'
            WHEN 60 THEN '及格'
        END
        AS '成绩'

DECLARE @score INT
SET @score = 100

SELECT CASE 
            WHEN @score >= 90 THEN '优秀'
            WHEN @score >= 80 THEN '良好'
            WHEN @score >= 70 THEN '中等'
            WHEN @score >= 60 THEN '及格'
            ELSE '不及格'
        END
        AS '成绩'

WHILE Boolean_expression 
     { sql_statement | statement_block | BREAK | CONTINUE }

DECLARE @i int;
SET @i = 0;
WHILE(@i < 10)
BEGIN
    SET @i = @i + 1;
    IF(@i % 2 = 0)
    BEGIN
        PRINT('跳过2的倍数' + CAST(@i AS varchar));
        CONTINUE;
    END
    ELSE IF (@i = 7)
    BEGIN
        PRINT('到' + CAST(@i AS varchar) + '就跳出循环');
        BREAK;
    END
    PRINT @i;
END

BEGIN
    PRINT(1);
    PRINT(2);
    RETURN;
    PRINT(3);    --在RETURN之后的代码不会被执行，因为会跳过当前批处理
END
GO
BEGIN
    PRINT(4);
END

DECLARE @i int;

SET @i = 1;
SET @i = 2;
SET @i = 3;
SET @i = 4;
GOTO ME;
SET @i = 5;　　--这行被跳过了
SET @i = 6;　　--这行被跳过了
SET @i = 7;　　--这行被跳过了

ME:PRINT('跳到我了?');
PRINT @i

跳到我了?
4

WAITFOR 
{
    DELAY 'time_to_pass' 
  | TIME 'time_to_execute' 
  | [ ( receive_statement ) | ( get_conversation_group_statement ) ] 
    [ , TIMEOUT timeout ]
}

WAITFOR DELAY '01：00'

WAITFOR TIME '01：00'