我有一个针对data.stackexchange.com运行的相当复杂的SQL查询。该查询可以在this link找到(并粘贴在下方)。
DECLARE @Location varchar(128) = ##Location:string##
DECLARE @RepLimit int = ##RepLimit:int##
SELECT Users.DisplayName,
Users.Id,
Users.WebsiteUrl,
Users.Reputation,
(
SELECT COUNT(*)
FROM Posts
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Posts.PostTypeId = 2
AND Tags.Id = 3 -- Javascript
AND Posts.OwnerUserId = Users.Id
) AS JavascriptCount,
(
SELECT COUNT(*)
FROM Posts
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Posts.PostTypeId = 2
AND Tags.Id = 5 -- PHP
AND Posts.OwnerUserId = Users.Id
) AS PhpCount,
(
SELECT COUNT(*)
FROM Posts
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Posts.PostTypeId = 2
AND Tags.Id = 820 -- jQuery
AND Posts.OwnerUserId = Users.Id
) AS jQueryCount,
(
SELECT COUNT(*)
FROM Posts
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Posts.PostTypeId = 2
AND Tags.Id = 21 -- MySQL
AND Posts.OwnerUserId = Users.Id
) AS MySqlCount,
(
SELECT COUNT(*)
FROM Posts
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Posts.PostTypeId = 2
AND Tags.Id = 1386 -- Android
AND Posts.OwnerUserId = Users.Id
) AS AndroidCount,
(
SELECT COUNT(*)
FROM Posts
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Posts.PostTypeId = 2
AND Tags.Id IN (58338, 81106, 92809, 7003) -- IOS
AND Posts.OwnerUserId = Users.Id
) AS IosCount
FROM Users
WHERE Users.Reputation > @RepLimit
AND Users.Location = @Location
在上面的查询中,发生了一些事情:
DECLARE
d的数据(在本例中为Location和RepLimit)。我想改变两件事,但我对SQL Server不够熟悉,不知道它们是否可行(并且也不知道究竟要查询什么以找到我需要的结果)。这两个变化是:
DECLARE
d,如Location和RepLimit),或者作为5个单独的表单字段(将查询限制为最多5个不同的标签)有没有人有类似查询的经验(或类似问题,查询返回的实际列是动态的?)。任何帮助表示赞赏。
答案 0 :(得分:1)
至于您的第一个问题是优化查询的方法:
DECLARE @Location varchar(128) = ##Location:string##
DECLARE @RepLimit int = ##RepLimit:int##
SELECT Users.DisplayName,
Users.Id,
Users.WebsiteUrl,
Users.Reputation,
sum(case when Tags.Id = 3 then 1 else 0 end) as JavascriptCount,
sum(case when Tags.Id = 5 then 1 else 0 end) as PhpCount,
sum(case when Tags.Id = 820 then 1 else 0 end) as jQueryCount,
sum(case when Tags.Id = 21 then 1 else 0 end) as MySqlCount,
sum(case when Tags.Id = 1386 then 1 else 0 end) as AndroidCount,
sum(case when Tags.Id IN (58338, 81106, 92809, 7003) then 1 else 0 end) as IosCount
FROM Users
JOIN Posts ON Posts.OwnerUserId = Users.Id
JOIN PostTags ON Posts.ParentId = PostTags.PostId
JOIN Tags ON PostTags.TagId = Tags.Id
WHERE Users.Reputation > @RepLimit AND Posts.PostTypeId = 2
AND Users.Location = @Location
GROUP BY
Users.DisplayName,
Users.Id,
Users.WebsiteUrl,
Users.Reputation
关于你的第二个问题我 - 对堆栈交换表格一无所知 - 恐怕我无能为力。但是既然你提到逗号分隔列表,你可以利用SQL的CHARINDEX()函数来查找参数中的Tags.Id。是这样的:
case when CHARINDEX(','+convert(varchar,Tags.Id)+',',','+@List1+',') <> 0 then 1 else 0 end