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MySQL之select簡單使用

Select * from table_name

Select column_name_1,column_name_2 from table_name

 

Select * from student where 姓名=‘劉婷’and 所在班級=2

Select * from student where 成績 between 90 and 100

Select * from student where 姓名 like ‘劉%’

Select * from student where 備註 is NOT NULL

 

Select TOP 5 * from student

 

Select column_name AS column_alias from table_name

 

Select * from student order by 成績 DESC

Select * from student order by 成績 ASC

 

Select SUM(成績) 總成績 from student

Select AVG(成績) 平均成績 from student

Select MAX(成績) 最高分,MIN(成績) 最低分 from student

Select COUNT(*) 總行數 from student

 

Select 所在班級,SUM(成績) AS 總成績 from student GROUP BY 所在班級

         查詢student表中每個班級的總成績

Select 所在班級,SUM(成績) AS 總成績 from student GROUP BY 所在班級 HAVING SUM(成績)>200

         查詢student表中總成績大於200的班級

 

Select * into student_bak from student

         將student表的資料插入到新表student_bak中

Select * into student_2 from student WHERE 所在班級=2

         將student表中2班的學生資訊儲存到表student_2中

 

左連線(A表全部顯示,B表顯示同A裡相同的部分)

Select A.name 姓名A,A.school 學校A,B.name 姓名B,job 職業B from A left join B on A.name=B.name

右連線(B表全部顯示,A表顯示同B裡相同的部分)

Select A.name 姓名A,A.school 學校A,B.name 姓名B,job 職業B from A right join B on A.name=B.name

內連線(顯示AB表姓名相同的部分)

Select A.name 姓名A,A.school 學校A,B.name 姓名B,job 職業B from A inner join B on A.name=B.name

外連線(顯示AB表全部的資訊,其他為NULL)

Select A.name 姓名A,A.school 學校A,B.name 姓名B,job 職業B from A full join B on A.name=B.name