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