子查询

子查询详解

一、使用 IN 关键字的子查询

SELECT [id]
      ,[name]
      ,[age]
      ,[birthday]
      ,[nation]
      ,[classname]
      ,[sex]
  FROM [School].[dbo].[Student]
WHERE name IN (
    SELECT DISTINCT name FROM [Money] WHERE je > 10
)Code language: CSS (css)

二、使用 EXISTS 关键字

SELECT [id]
      ,[name]
      ,[age]
      ,[birthday]
      ,[nation]
      ,[classname]
      ,[sex]
  FROM [School].[dbo].[Student] as s
WHERE EXISTS (
    SELECT 1 FROM [Money] m WHERE m.je > 10 AND m.name = s.name
)Code language: JavaScript (javascript)

类似循环逻辑：

for (Person p in personlist)
{
}

boolean Fun(Person s)
{
	
}Code language: CSS (css)

三、比较运算符

select * from dbo.student s
where s.number > any(select 99999999999)Code language: CSS (css)

select * from dbo.student s
where s.number > all(select number from dbo.student)Code language: CSS (css)

SELECT * FROM [Money] m1
WHERE m1.je > ALL(
    SELECT lx FROM [Money]
)Code language: CSS (css)