Question

我的要求就像从sql中选择前5行，如果它只包含2行，那么默认情况下它会在剩下的3行中显示一些文字说“无数据”。所有条件都一样。

对于选择前5行，但它只包含3行，则查询将返回
ROW1
行2
ROW3
没有数据
没有数据

Answer 1

请尝试：

select top 5 Col 
from(
    select 0 srt, Col from YourTable

    union all

    select 1 srt, 'No Data' Col union all
    select 1 srt, 'No Data' Col union all
    select 1 srt, 'No Data' Col union all
    select 1 srt, 'No Data' Col union all
    select 1 srt, 'No Data' Col
)x
order by srt

Answer 2

这将更加动态

    declare @t TABLE (id int,TerminalID varchar(15))
    declare @top int
        set @top = 5

    declare @c int --Holds Total
        set @c = 0
    while (@c < @top) begin
        insert into @t (id, TerminalID) values (@c, 'No Data')
        set @c = @c + 1
    end

    select top 5 * from
    (
    select top 5 TerminalID from AccessLog-- [where colo0 = ???]
    union all
    select TerminalID from @t
    ) x

Answer 3

/* assuming the column width is 8 characters and datatype is varchar */    
DECLARE @NoDataTable AS TABLE(column1 VARCHAR(8)) 

DECLARE @i AS INT
SET @i = 0

WHILE(@i<5)
BEGIN

    insert into @NoDataTable (column1)
    values('No Data');

    set @i = @i+1
end

select top 5 * 
from
(
     select column1  from TestTable
     union all 
     select column1 from @NoDataTable
) as T

Answer 4

WITH cte AS
(
    SELECT YourColumn FROM YourTable
    UNION ALL
    SELECT TOP 5 NULL FROM YourTable
)           
SELECT TOP 5 COALESCE(YourColumn, 'No Data')
FROM cte

无论如何，获得最多的行数

4 个答案: