SQL处理表结构的基本方法整理(创建表,关联表,复制表)
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2024-03-21 14:14:28
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复制表结构及数据到新表
CREATE TABLE 新表 SELECT * FROM 旧表
只复制表结构到新表
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
复制旧表的数据到新表(假设两个表结构一样)
INSERT INTO 新表 SELECT * FROM 旧表
复制旧表的数据到新表(假设两个表结构不一样)
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;
说明:复制表(只复制结构,源表名:a 新表名:b)
SQL: select* into b from a where 1<>1
说明:拷贝表(拷贝数据,源表名:a 目标表名:b)
SQL: insert into b(a, b, c) select d,e,f from b;
其他说明
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
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