SQL处理表结构的基本方法整理（创建表，关联表，复制表）

CREATE TABLE 新表 SELECT * FROM 旧表

CREATE TABLE 新表 SELECT * FROM 旧表 WHERE 1=2

即:让WHERE条件不成立.

方法二:(由tianshibao提供) CREATE TABLE 新表 LIKE 旧表

INSERT INTO 新表 SELECT * FROM 旧表

INSERT INTO 新表(字段1,字段2,.......) SELECT 字段1,字段2,...... FROM 旧表
如果是 SQL SERVER 2008 复制表结构，使用如下方法：

在表上面右击——编写表脚本为:——Create到——新查询编辑器窗口，你也可以保存为sql文件，

新查询编辑器窗口的话在最上面一条把use databasename改成你要复制过去的数据库名称

如果遇到：

IDENTITY_INSERT 设置为 OFF 时,不能向表 ‘id’ 中的标识列插入显式值。

插入数据的时候不要为id列指定值，也就是 insert into table ( …)语句中,括号中的字段中不要包含id列。

SQL SERVER 2008
 insert into b(a, b, c) select d,e,f from b;

SQL: select* into b from a where 1<>1

SQL: insert into b(a, b, c) select d,e,f from b;

说明：显示文章、提交人和最后回复时间

SQL: selecta.title,a.username,b.adddate fromtable a,(selectmax(adddate) adddate fromtable wheretable.title=a.title) b

说明：外连接查询(表名1：a 表名2：b)

SQL: selecta.a, a.b, a.c, b.c, b.d, b.f froma LEFT OUT JOIN b ON a.a = b.c

说明：日程安排提前五分钟提醒

SQL: select* from 日程安排 where datediff('minute',f开始时间,getdate())>5

说明：两张关联表，删除主表中已经在副表中没有的信息

SQL:

delete from info wherenot exists ( select* from infobz where info.infid=infobz.infid )

说明：–

SQL:

SELECT A.NUM, A.NAME, B.UPD_DATE, B.PREV_UPD_DATE

FROM TABLE1,

(SELECT X.NUM, X.UPD_DATE, Y.UPD_DATE PREV_UPD_DATE

FROM (SELECT NUM, UPD_DATE, INBOUND_QTY, STOCK_ONHAND

FROM TABLE2

WHERE TO_CHAR(UPD_DATE,'YYYY/MM') = TO_CHAR(SYSDATE,'YYYY/MM')) X,

(SELECT NUM, UPD_DATE, STOCK_ONHAND

FROM TABLE2

WHERE TO_CHAR(UPD_DATE,'YYYY/MM') =

TO_CHAR(TO_DATE(TO_CHAR(SYSDATE,'YYYY/MM') ||'/01','YYYY/MM/DD') - 1,'YYYY/MM') ) Y,

WHERE X.NUM = Y.NUM （+）

AND X.INBOUND_QTY + NVL(Y.STOCK_ONHAND,0) <> X.STOCK_ONHAND ) B

WHERE A.NUM = B.NUM

说明：–

SQL:

select* from studentinfo where not exists(select * from studentwhere studentinfo.id=student.id) and 系名称='"&strdepartmentname&"'and 专业名称='"&strprofessionname&"'order by 性别,生源地,高考总成绩

说明：

从数据库中去一年的各单位电话费统计(电话费定额贺电化肥清单两个表来源）

SQL:

SELECT a.userper, a.tel, a.standfee, TO_CHAR(a.telfeedate,'yyyy') AS telyear,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '01', a.factration)) AS JAN,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '02', a.factration)) AS FRI,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '03', a.factration)) AS MAR,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '04', a.factration)) AS APR,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '05', a.factration)) AS MAY,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '06', a.factration)) AS JUE,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '07', a.factration)) AS JUL,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '08', a.factration)) AS AGU,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '09', a.factration)) AS SEP,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '10', a.factration)) AS OCT,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '11', a.factration)) AS NOV,

SUM(decode(TO_CHAR(a.telfeedate,'mm'), '12', a.factration)) AS DEC

FROM (SELECT a.userper, a.tel, a.standfee, b.telfeedate, b.factration

FROM TELFEESTAND a, TELFEE b

WHERE a.tel = b.telfax) a

GROUP BY a.userper, a.tel, a.standfee, TO_CHAR(a.telfeedate,'yyyy')

说明：四表联查问题：

SQL: select * froma left inner joinb on a.a=b.b right inner join c on a.a=c.c innerjoin d on a.a=d.d where .....

说明：得到表中最小的未使用的ID号

SQL:

SELECT (CASE WHEN EXISTS(SELECT * FROM Handle b WHERE b.HandleID = 1) THEN MIN(HandleID) + 1 ELSE 1 END)as HandleID

FROM Handle

WHERE NOT HandleID IN (SELECT a.HandleID - 1 FROM Handle