sql server where 子句中的用例
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use case in where clause sql server
提问by user2085104
what im trying to do is to make a query consider or not a datetime value so i dont have to do this in a stored procedure
我想做的是让查询考虑或不考虑日期时间值，所以我不必在存储过程中执行此操作
if @considerDate =1
begin
select * from table
where dateCol = @date
end
else
begin
select * from table
end
i would like to do somethink like
我想做点什么
select * from table
where dateCol = ( case
when @date is not null
then @date
)
In an single query
在单个查询中
回答by John Woo
you just need to add ENDkeyword
你只需要添加END关键字
SELECT *
FROM tableName
WHERE dateCol = CASE WHEN @considerDate =1
THEN @date
ELSE dateCol
END
回答by sgeddes
If I'm understanding you correctly, this should work:
如果我正确理解你，这应该有效：
SELECT *
FROM Table
WHERE dateCol =
CASE WHEN @date is not null then @date ELSE dateCol END
回答by mattyc
if @considerDate =0
begin
-- set the variable to null so the select will return all rows from table
set @date = null
end
SELECT *
FROM table
WHERE dateCol = IsNull(@date, dateCol)
If you don't want to include the date parameter in your query, set the value to null and in your query you can use a null check to decide if it will apply the filter.
如果您不想在查询中包含日期参数，请将值设置为 null，并且在您的查询中，您可以使用 null 检查来决定它是否会应用过滤器。
