请教SQL IF 中加入UNION ALL???

[宇宙最强皮皮虾]

各位道友..

DECLARE @round INT
SELECT @round = 10
WHILE @round > 0
BEGIN
	SELECT
		*
	FROM
		t_project p
	WHERE
		p.id = 1263
	SET @round = @round - 1 ;

	--问题出在这里
	IF @round != 1
	BEGIN
		UNION ALL
	END

	
END

请问我如何才能判断如果round不等于1则在sql下面加入UNION ALL这个标签，否则不加入。

现在报错：[Err] 42000 - [SQL Server]关键字 'UNION' 附近有语法错误。

[宇宙最强皮皮虾]

解决了。我新建了一个临时表然后谢了存储过程循环向里面添加数据。

ALTER PROC p_agreementError @agreement_project_id int
AS 
DECLARE @round INT ,@start DATE 

if (SELECT (DATEDIFF(DAY,ap.start_date,ap.end_date) % ap.photoperiod) FROM t_agreement_project ap WHERE ap.id = @agreement_project_id) > 0
BEGIN
	SELECT @round = (DATEDIFF(DAY,ap.start_date,ap.end_date) / ap.photoperiod) + 1 FROM t_agreement_project ap WHERE ap.id = @agreement_project_id
END
ELSE
BEGIN
	SELECT @round = (DATEDIFF(DAY,ap.start_date,ap.end_date) / ap.photoperiod) FROM t_agreement_project ap WHERE ap.id = @agreement_project_id
END

SELECT @start = ap.start_date FROM t_agreement_project ap WHERE ap.id = @agreement_project_id
WHILE @round > 0
		BEGIN

			INSERT INTO t_agreement_error (agreementid,agreementprojectid,start_date,end_date,agreementerror) 
			SELECT a.id,ap.id,@start,(SELECT DATEADD(DAY, ap.photoperiod, @start) FROM t_agreement_project ap WHERE ap.id = @agreement_project_id),
			(CASE WHEN p.photo_time BETWEEN @start AND DATEADD(DAY, ap.photoperiod, @start) THEN '正常' ELSE '异常' END)
			FROM t_agreement a
			LEFT JOIN t_agreement_project ap ON a.id = ap.agreement_id
			LEFT JOIN t_photograph p ON ap.id = p.agreement_projectid
			WHERE
				ap.id = @agreement_project_id and @start < GETDATE()
				--(p.id is null and @start < ap.end_date) 
				--or
				--(p.photo_time BETWEEN @start AND DATEADD(DAY, ap.photoperiod, @start) and @start < ap.end_date)

		SELECT @start = DATEADD(DAY, ap.photoperiod, @start) FROM t_agreement_project ap WHERE ap.id = @agreement_project_id
		
		SET @round = @round - 1
	END

[lzw_0736]

SQL語句用變量

[唐诗三百首]

应该用动态SQL实现,

[tcmakebest]

楼主的示例完全不能体现楼主要干嘛, 要 UNION 1-10吗, 应该有更好的解决办法.

[还在加载中灬]

如果要按你原本的想法，只有用动态执行，不过感觉你的业务需要可以有别的方式实现。