所有的sql聚合函数的应用例题 谢谢

Posted 2023-03-18

参考技术A WHERE
type
=
'business'
下面是结果集：
--------------------------
-----------
6,281.25
30788
(1
row(s)
affected)
------------------------------------------------
MAX
求最大值
例题：简单的就不写了
-------------------------------------------------
BINARY_CHECKSUM
在表中任一行上计算的
BINARY_CHECKSUM(*)
返回相同的值，只要随后没有修改行。
BINARY_CHECKSUM(*)
将为大多数（但不是全部）行更改返回不同的值，并可用于检测大多数行修
改。
例题：本例使用
BINARY_CHECKSUM
来检测
Northwind
数据库的
Products
表中一行的改变。
/*Get
the
checksum
value
before
the
values
in
the
specific
rows
(#13-15)
are
changed.*/
USE
Northwind
GO
CREATE
TABLE
TableBC
(ProductID
int,
bchecksum
int)
INSERT
INTO
TableBC
SELECT
ProductID,
BINARY_CHECKSUM(*)
FROM
Products
/*TableBC
contains
a
column
of
77
checksum
values
corresponding
to
each
row
in
the
Products
table.*/
--A
large
company
bought
products
13-15.
--The
new
company
modified
the
products
names
and
unit
prices.
--Change
the
values
of
ProductsName
and
UnitPrice
for
rows
13,
14,
and
15
of
the
Products
table.*/
UPDATE
Products
SET
ProductName='Oishi
Konbu',
UnitPrice=5
WHERE
ProductName='Konbu'
UPDATE
Products
SET
ProductName='Oishi
Tofu',
UnitPrice=20
WHERE
ProductName='Tofu'
UPDATE
Products
SET
ProductName='Oishi
Genen
Shouyu',
UnitPrice=12
WHERE
ProductName='Genen
Shouyu'
--Determine
the
rows
that
have
changed.
SELECT
ProductID
FROM
TableBC
WHERE
EXISTS
(
SELECT
ProductID
FROM
Products
WHERE
Products.ProductID
=
TableBC.ProductID
AND
BINARY_CHECKSUM(*)
<>
TableBC.bchecksum)
下面是结果集：
ProductID
13
14
15
----------------------------------------------