| 经典sql |
| 总结一些经常用到或碰到的SQL语句，希望能与大家分享，同时也希望大家能提供更多的精妙SQL语句..... 1、delete table1 from (select * from table2) as t2 where table1.id=t2.id 2、truncate table table1 (不在事务日志中做记录，比delete table快，但不能激活触发器) 3、update table1 set column=column+1 where id=(select id from table2) 4、update table1 set column=column+1 from table1,table2 where table1.id=table2.id 5、select top n [Percent] * from table1 '输出百分比记录 6、select id,column1 * column2 as column from table1 '可算明白as的用法了 7、select * from table1 where column1 like 'SQL#_G_O' escape '#' '单匹配 8、select table1.id from table1 where not exists (select table2.id from table2 where table1.id=table2.id) '这个应该比not in快一些 9、select table1.id from table1,table2 where table1.id<>table2.id '看复合查询机制 10、select table1.id from table1,table2,(select id from table3) as t3 where table1.id=table2.id and table2.id=t3.id '有些类似[1]了...... 11、select * from table1 where column1 like '[A]%' or like '[^B]%' 12、select @column1=column1 from table1;select @column1 as column1 '存储到自定义变量 13、select * from table1 where contains(column1,'char1 or char2*') '全文索引 14、select * from table1 where contains(column1,'前有 near 中有 near 后有') 15、select * from table1 where contains(column1,'formsof(inflectional,go)') '派生 16、select * from table1 where contains(description,'isabout(apple weight(.9),boy weight(.8),china weight(.7))') '权重 17、select * from table1 where freetext(column1,'char') '仅支持文字不支持表达式搜索 18、insert into table1 select column1,count(column1) from table2 group by column1 '统计 ----------------------------------------------------------------------------------------- 1 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 2 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; 3 说明：显示文章、提交人和最后回复时间 SQL: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4 说明：外连接查询(表名1：a 表名2：b) SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5 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 6 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 where not exists ( select * from infobz where info.infid=infobz.infid ) 7 说明： 从数据库中去一年的各单位电话费统计(电话费定额和电话费清单两个表来源） 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') 8 说明：四表联查问题： SQL: select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 9 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 a) 10 说明：模糊查询，单字匹配(短横线代表待匹配内容) select * from table where field1 like 'A_B_C' 11 说明：as的用法 select id,column1 * column2 as column from table1 |