10.20 MYSQL尋找總結

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a、條件判斷where

select * from 表 where id > 1 and name != ‘alex‘ and num = 12;select * from 表 where id between 5 and 16;select * from 表 where id in (11,22,33)select * from 表 where id not in (11,22,33)select * from 表 where id in (select nid from 表)

b、萬用字元like（模糊尋找）

select * from 表 where name like ‘liu%‘  # liu開頭的所有（多個字串）select * from 表 where name like ‘liu_‘  #liu開頭的所有（一個字元）select * from 表 where name like ‘%liu_‘select * from 表 where name like ‘_liu_‘select * from 表 where name like ‘%liu%‘select * from 表 where name like ‘_liu%‘

c、限制limit(分頁)

select * from 表 limit 5;            - 前5行select * from 表 limit 4,5;          - 從第4行開始的5行select * from 表 limit 5 offset 4    - 從第4行開始的5行

d、排序asc，desc

select * from 表 order by 列 asc              - 根據 “列” 從小到大排列select * from 表 order by 列 desc             - 根據 “列” 從大到小排列select * from 表 order by 列1 desc,列2 asc    - 根據 “列1” 從大到小排列，如果相同則按列2從小到大排序

 e、分組group by

select num from 表 group by numselect num,nid from 表 group by num,nidselect num,nid from 表  where nid > 10 group by num,nid order by nid descselect num,nid,count(*),sum(score),max(score),min(score) from 表 group by num,nidselect num from 表 group by num having max(id) > 10 特別的：group by 必須在where之後，order by之前

f、組合union、union all

組合，自動處理重合（去掉相同）    select nickname from A union select name from B 組合，不處理重合（所有的都顯示）    select nickname from A union all select name from B

g、連表join

無對應關係則不顯示    select A.num, A.name, B.name from A,B Where A.nid = B.nid 無對應關係則不顯示    select A.num, A.name, B.name from A inner join B    on A.nid = B.nid A表所有顯示，如果B中無對應關係，則值為null    select A.num, A.name, B.name from A left join B on A.nid = B.nid B表所有顯示，如果B中無對應關係，則值為null    select A.num, A.name, B.name from A right join B on A.nid=B.nid

10.20 MYSQL尋找總結