sql 分組查詢問題

2024-08-31 00:59:07

字體：大中小

來源：轉載

供稿：網友

情景一：
表中數據
name score
aaa 11
aaa 19
bbb 12
bbb 18
ccc 19
ddd 21
期望查詢結果如下
name score
aaa 30
bbb 30
ccc 19
ddd 21

復制代碼代碼如下:

---檢查表是否存在
if exists(select * from sysobjects where)
drop table testSum
go
---創建表
create table testSum
(
tid int primary key identity(1,1),
tname varchar(30) null,
tscor int null
)
go
insert into testSum (tname,tscor)
select 'aaa',11
union all
select 'aaa',19
union all
select 'bbb',12
union all
select 'bbb',18
union all
select 'ccc',19
union all
select 'ddd',21
---查詢語句
select tname ,sum(tscor) from testSum group by tname
---只查詢tscor總和為30的
select tname ,sum(tscor) from testSum group by tname having sum(tscor)=30

情景二：
姓名科目分數
張三語文 30
張三數學 50
張三英語 70
李四語文 50
李四數學 80
李四英語 90

期望查詢結果：

姓名語文數學英語
張三 30 50 70
李四 50 80 90

復制代碼代碼如下:

---檢查表是否存在
if exists(select * from sysobjects where)
drop table testScore
go
---創建表
create table testScore
(
tid int primary key identity(1,1),
tname varchar(30) null,
ttype varchar(10) null,
tscor int null
)
go
---插入數據
insert into testScore values ('張三','語文',90)
insert into testScore values ('張三','數學',20)
insert into testScore values ('張三','英語',50)
insert into testScore values ('李四','語文',30)
insert into testScore values ('李四','數學',47)
insert into testScore values ('李四','英語',78)
---查詢
select tname as '姓名' ,
max(case ttype when '語文' then tscor else 0 end) '語文',
max(case ttype when '數學' then tscor else 0 end) '數學',
max(case ttype when '英語' then tscor else 0 end) '英語'
from testScore
group by tname

情景三：
表:table1
字段：id , name
內容：
----------------
1,aaa
1,bbb
2,ccc
2,ddd
3,eee
3,fff
--------------
希望結果：
---------------------
1 aaa bbb [aaa bbb之間半角空格區分，以下類似]
2 ccc ddd
3 eee fff

復制代碼代碼如下:

f exists(select * from sysobjects where)
drop table test1
go
create table test1
(
tid int primary key identity(1,1),
tnum int null,
tname varchar(30) null
)
go
insert into test1 values (1,'aa')
insert into test1 values (1,'bb')
insert into test1 values (2,'cc')
insert into test1 values (2,'dd')
insert into test1 values (3,'ee')
insert into test1 values (3,'ff')
SELECT * FROM ( SELECT DISTINCT tnum FROM test1
)A
OUTER APPLY(
SELECT tname= STUFF(REPLACE(REPLACE(
(
SELECT tname FROM test1 N
WHERE tnum = A.tnum
FOR XML AUTO
), '<N tname="', ' '), '"/>', ''), 1, 1, '')
)N

情景四：
我需要將表tb中的數據select出來，得到下面第二個表的數據，如何寫select語句？
表tb
id a flag class
----------+---------+--------+---------
1 2 1 A
2 2 1 A
3 4 1 A
4 5 2 A
5 3 2 A
6 4 1 A
7 2 1 A
8 3 2 A
9 4 2 A
10 5 3 A
11 5 1 B
12 2 1 B
13 3 1 B
14 4 1 B
15 2 3 B
16 7 3 B
17 3 2 B
18 4 1 B
19 5 1 B
20 2 2 B
21 1 1 B
22 1 1 C
23 2 3 C
24 6 3 C
25 3 2 C
...
需要選取出如下的表，按class列進行分組，a1,a2,a3字段分別為flag=1、2、3時tb表中a字段的求和
選取后
a1 a2 a3 class
-----------+------------+-----------------+--------------
sum(a) sum(a) sum(a) A
sum(a) sum(a) sum(a) B
sum(a) sum(a) sum(a) C
sum(a) sum(a) sum(a) D
sum(a) sum(a) sum(a) E
sum(a) sum(a) sum(a) F
sum(a) sum(a) sum(a) G

復制代碼代碼如下:

---檢查表是否存在
if exists(select * from sysobjects where)
drop table testFlag
go
---創建表
create table testFlag
(
tid int primary key identity(1,1),
tname varchar(30) null,
tflag int null,
tscor int null
)
go
---插入數據
insert into testFlag (tname,tflag,tscor)
select 'aaa',1,11
union all
select 'aaa',2,19
union all
select 'aaa',3,12
union all
select 'aaa',1,18
union all
select 'aaa',2,19
union all
select 'aaa',3,21
union all
select 'bbb',1,11
union all
select 'bbb',2,19
union all
select 'bbb',3,12
union all
select 'bbb',1,18
union all
select 'bbb',2,19
union all
select 'bbb',3,21
----查詢語句
select distinct tname,(select sum(tscor) from testFlag where tflag=1 and testFlag.tname = t.tname) as 'flag1',(select sum(tscor) from testFlag where tflag=2 and testFlag.tname = t.tname) as 'flag2',(select sum(tscor) from testFlag where tflag=3 and testFlag.tname = t.tname) as 'flag3' from testFlag t group by tname,tflag