在SQL Server中使用伪数据的查询结果集中添加额外的行

Question

我有这张桌子，说学生。如果表中有2个学生，并且结果集给出2行，那么无论我说“ type,symbol,price,quantity,expirydate,strikeprice,amendtime,id,parentid T,ICICIBANK,1000,100,20121210,120,20121209103030,1234,0 T,AXISBANK,1000,100,20121210,120,20121209103031,1235,0 T,SBIBANK,1000,100,20121210,120,20121209103032,1236,0 P,ICICIBANK,1100,100,20121210,120,20121209103030,1237,1234 P,AXISBANK,1000,100,20121210,120,20121209103031,1238,1235 T,ICICIBANK,1000,100,20121210,120,20121209103035,1239,0 T,.CITIBANK,1000,101,20121210,120,20121209103036,1240,0 P,ICICIBANK,1100,100,20121210,120,20121209103030,1241,1234 P,ICICIBANK,1100,100,20121210,120,20121209103035,1242,1239 ”还是类似的东西，我都想在其中添加5个带有伪数据的行。

Dummy Record

如果上述查询的输出是这样的。

SELECT FirstName, (SELECT COUNT(*) FROM Student) Total
FROM Student

我希望输出像这样

FirstName         Total
Isaac Frempong    2
Erick Ortiz       2

我希望这是可以实现的，我无法在这里弄清楚如何应用CASE或IF语句。也许有人可以帮忙。

Answer 1

一种方法是使用VALUES()语句构造行：

SELECT FirstName, COUNT(*) OVER () as Total
FROM Student
UNION ALL
SELECT 'Dummy', (SELECT COUNT(*)  FROM Student)
FROM (VALUES (1), (2), (3), (4), (5)) v(n);

编辑：

如果您始终需要7行，请使用算术：

SELECT FirstName, COUNT(*) OVER () as Total
FROM Student
UNION ALL
SELECT 'Dummy', s.total
FROM (VALUES (1), (2), (3), (4), (5), (6), (7)) v(n) CROSS JOIN
     (SELECT COUNT(*) as total FROM Student) s
WHERE v.n <= 7 - s.total;

s

Answer 2

这是处理表变量的代码，我称为 @students

请用您自己的桌子替换

我已在此表中填充了一些数据，并测试了不同的案例（记录数小于7或大于7，并按您的意愿工作！）

1）首先创建一个名为@mytable的变量表，该表将由n条记录填充

如果学生表中的记录数等于或小于7，则

n将为7

n将是学生表中的记录数（如果大于7）

2）然后使用CTE，row_number（）函数在要添加记录号的学生表之间建立右外部联接。

declare @students as table(id int identity(1,1),firstname nvarchar(50))

insert into @students(firstname) values
('Ali ben Hassine'),
('Mohamed el Aabed'),
('Ali ben Hassine'),
('Mohamed el Aabed'),
('Mohamed el Aabed'),
('Tahar Harbi'),
('Hassine Ayari'),
('Ihsen Trabelsi'),
('Marwa Mostari'),
('Mourad Zmerli'),
('Hafedh Gabsi'),
('Miloud Filali');

declare @mytab as table(n int)
declare @n as int
select @n=count(distinct(firstname))  from @students 
if @n<7 set @n=7
declare @i as int
set @i=1
while @i <@n+1
begin
insert into @mytab values(@i)
set  @i=@i+1
end;



with cte as
(select row_number() over(partition by 1 order by firstname) r#,firstname,count(1) Total from @students group by firstname)
select isnull(cte.firstname,'Dummy') firstanme,isnull(cte.total,2) Total from cte
right outer join @mytab t2 on cte.r#=t2.n
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