我們以電信的收費系統爲例的SQL數據庫查詢：
數據庫biao1 裏面有幾個表：call、 call-history
1、-------從biao1的數據庫裏查詢表call的全部信息-------
use biao1
select * from call
2、將查詢的列名翻譯爲你知道的漢語
select id '編號',starttime '開始時間',endtime '結束時間',phonenumber '電話號碼',calltype '電話類型' from call
3、查詢某一電話號碼出現的總數
select COUNT(*)from call where phonenumber=13001013336
4、查詢在某時間段內所有電話號碼包含“333”的長途，並按開始時間降序排列
select * from call where phonenumber like '%333%' and starttime between '2010-08-01 00:00:00' and '2010-08-05 23:23:23' and calltype=1
order by starttime DESC
5、查詢某一電話號碼在某時間段內的數據
select * from call where starttime>'2010-08-01 00:00:00' and starttime<='2010-08-06 00:00:00' and phonenumber=13001013336
6、查詢某一號碼的市話費用總和
select sum(DATEDIFF(mi,starttime,endtime))*0.2 as '市話費'
from call where calltype=0 and phonenumber=13001013336
7、查找某電話的長途通話中最大通話時間是多少
select max(DATEDIFF(mi,starttime,endtime))as '長途最大通話時間'
from call where calltype=1 and phonenumber=13001013336
8、查詢某電話所有市話裏通話最短的時間
select min(DATEDIFF(mi,starttime,endtime))as '市話最小通話時間'
from call where calltype=0 and phonenumber=13001013336
9、查詢某電話所有市話的平均話費
select '用戶13001013336的平均市話費爲：' + cast((avg(DATEDIFF(mi,starttime,endtime))*0.2)as varchar(10))as '電話費'
from call where calltype=0 and phonenumber=13001013336
10、從表call和表call-history中查找電話號碼相同的，且符合某些條件的數據
select * from call INNER JOIN [call-history] ON CALL.phonenumber=[call-history].phonenumber
where call.calltype=0 and [call-history].calltype=1 and call.id<100010 and [call-history].id>100015
11、把所有數據複製到表a 中
select * into a from call
12、把查詢到的結果寫入到表b中
select call.phonenumber into b from call
where starttime between '2010-08-01 00:00:00' and '2010-08-05 23:23:23' and calltype=0
