（3.13）T-SQL 简单查询

Posted 2020-06-22

1.普通查询：

select * from Info #查询Info 表所有的内容

select Name,Code from Info #查询Info 表的Name,Code 列

2.条件查询

select * from Info where Sex=1#查询Info表中 Sex 为1的单元格

select * from Info where Sex=1 and Nation=‘n001‘ #查询Info表中Sex=1 并且 Nation=n001的数据

select * from Info where Sex=1 or Nation=‘n001‘   #查询Info表中Sex=1 或者 Nation=n001的数据

3.模糊查询

select * from ChinaStates where AreaName like ‘中%‘  #查询Chinastates表 AreaName列中以中开头的数据

select * from ChinaStates where AreaName like ‘%中%‘#查询ChinaStates表中AreaName列中包含中的数据

select * from ChinaStates where AreaName like ‘_中%‘ #查询ChinaStates表中AreaName列中第二个字为中的数据

4.排序查询

select * from Car order by Code desc #查询Car表中按Code列降序排列

select * from Car order by Code asc  #查询Car表中按Code列升序排列

select * from Car order by Code ,Brand#查询Car表中按Code,Brand排列

5.统计查询（聚合函数）

select count(Oil)  from Car #查询Car 表中 Oil 列中数据的条数

select max(Oil) from Car #查询Car表中Oil列中最大的数据

select min(Oil) from Car  #查询Car表中Oil列中最小的数据

select avg(Oil) from Car  #查询Car表中Oil列数据的平均值

6.分组查询

select Code,Brand, Count(*) from Car group by Brand# 查询Car表中分组查看每组的数据条数

select * from Car group by Brand having count(*)>1  #查询Car表中分组查看Brand中数据条数大于2的

7.分页查询

select * from Car limit 5,5  #查询Car表中跳过5条数据取5条数据