導讀：
select * from txt1
select * from txt2
select * from txt1 where name in (select name from txt2 where chk = 0)
select * from txt1 where name not in (select name from txt2 where chk = 0)
select * from txt1 inner join txt2 on txt1.name = txt2.name
select * from txt1 left join txt2 on txt1.name = txt2.name
select * from txt1 right join txt2 on txt1.name = txt2.name
select * from txt1,txt2 where txt1.name = txt2.name Order By txt2.ID Desc
select Txt1.name,Sum(Txt1.Sumint) from txt1,txt2 where txt1.name =txt2.name Group by txt1.name
select count(Txt1.name),sum(sumint) from txt1,txt2 where txt1.name =txt2.name having sum(sumint)<10
select count(Txt1.name),sum(sumint) from txt1,txt2 where txt1.name =txt2.name having Sum(sumint) >50
select * from txt1,txt2 where txt1.name <>txt2.name Order by Txt1.Name compute Sum(sumint) by txt1.name
insert into txt3 select name,Sumint from txt1
In:等值連線，用來查詢多表相同欄位的記錄
Not In:非等值連線，用來查詢不存在的記錄
Inner join:內連線，主要用來查詢都符合條件的記錄
Left join:左連線，主要用來查詢左邊有，右邊沒有的用空值表達
Right join:右連線，主要用來查詢右邊有，左邊沒有的用空值表達
Order By:升序 Asc 降序 Desc
Group By:分組排序 按欄位分組(如按班級分),使用的都要有集合函式存在
Having :對分組條件進行判斷,使用都要確保每個欄位都要用集合函式
COMPUTE BY：子句使您得以用同一 SELECT 語句既檢視明細行，又檢視彙總行。可以計運算元組的彙總值，也可以計算整個結果集的彙總值。
行聚合函式名稱；例如，SUM、AVG、MIN、MAX 或 COUNT
insert into:主要把查詢的語句插入到新表。
txt1表的資料
ID Name SumInt
1 張三 55
2 李四 85
3 王五 85
4 趙六 855
txt2表的資料
ID Name Chk
1 張三 0
2 李四1 1
3 王五 0
4 趙六 0

本文轉自

http://hi.baidu.com/qzrc/blog/item/ff7ad688bc548394a4c272ce.html