sql - 如何在sql server的列中获取一些值

Question

我在 JobDetails 表中有一个工作名称列。像这样

job Name

A_1
A_2
B_1
B_2
B_3

我像这样搜索最大数量

SELECT MAX(JobDetails.[Job Name])
FROM Monara.JobDetails 
WHERE 
    ( [Job Name] like 'B_%' )

结果是 B_3

但我只想得到3个。

我该怎么做？

Answer 1

我拒绝创建包含空格的列

下划线是一个通配符，使用Like时应小心处理

create table JobDetails ([JobName] varchar(10))
insert JobDetails values('A_1'),('A_2'),('B_1'),('B_2'),('B_3')

SELECT max(cast(stuff(JobName, 1, patindex('%[_]%', JobName), '') as int)) 
FROM JobDetails
WHERE JobName like 'B[_]%'
-- added check to prevent most bad data
and IsNumeric(stuff(JobName, 1, patindex('%[_]%', JobName), '')) > 0

Answer 2

试试这个代码：

SELECT  SUBSTRING(JobDetails.[Job Name],
                  ( SELECT  CHARINDEX('_', JobDetails.[Job Name])
                  ) + 1,
                  LEN(JobDetails.[Job Name]) - 
                  CHARINDEX('_', JobDetails.[Job Name])
                  + 1)
FROM    Monara.JobDetails
WHERE   [Job Name] LIKE 'B_%'

Answer 3

SELECT count(JobDetails.[Job Name])
FROM Monara.JobDetails
WHERE [Job Name] like 'B_%'