1. 講師：戴志華 hana@arbor.ee.ntu.edu.tw 國立台灣大學電機工程研究所
Visual Basic 程式設計
講師：戴志華
國立台灣大學電機工程研究所

2. 第十五章 資料庫III
SQL

3. SQL
ORDER BY: 排序
SELECT au_id, author FROM authors ORDER BY au_id [ASC|DESC]

4. SQL(cont’d) Order by 之後的欄位可用數字代替 Ex:
Select id, name, score from student order by 3
Order by 1, 3, 2

5. SQL(cont’d) Adodc1.visible=false Adodc1的屬性對話盒RecordSource
CommandType=1-adCmdText
CommandText= select * from authors
Private Sub Command1_Click()
Adodc1.RecordSource = Text1.Text
Adodc1.Refresh
End Sub

6. SQL(cont’d) Aggregate function(統計用的函數) SUM:計算總和 AVG:計算平均 MAX:找出最大值
MIN:找出最小值
COUNT:計算記錄數量
Distinct Count:找出不同的值，再計算數量

7. FROM authors WHERE author like ‘a%’
SQL(cont’d)
Aggregate function Example
SELECT COUNT (id) as count1 from student
SELECT COUNT(author) FROM authors WHERE author like ‘a%’
FROM authors WHERE author like ‘a%’
SELECT COUNT(author)

8. Examples Employee_TBL Id Last_name First_name pager 1 Stephens Tina 2
Plew
Linda 3
Glass
Brandon 4
Jacob 5
Wallace
Mariah 6
Spurgeon
Tiffany

9. Examples (cont’d) Select count(id) from Employee_TBL 6 2
Select count(pager) from Employee_TBL 2
Select count(*) from Employee_TBL
Select count(distinct (Last_name)) from Employee_TBL 5

10. Examples Select count(id) as count1 from student where name like ‘小%’
select max ( chinese ) as maxchinese, min(chinese) as minchinese from student
select max(chinese) as maxchiniese, min(chinese) as minchinese from student group by class
select max(chinese) as maxchiniese, min(chinese) as minchinese, class from student group by class

11. 計算每個出版社(PubID)有出版幾本書
SQL(cont’d)
GROUP BY 分組
SELECT SEX, AVG(SCORE) From student GROUP BY SEX ORDER BY 2
SELECT PubID, COUNT(PubID) From Titles GROUP BY PubID ORDER BY PubID
計算每個出版社(PubID)有出版幾本書

12. SQL(cont’d) Having 子句 Select city, AVG(salary) from emp_tbl
Group by city
Having AVG(salary) >20000
Where group byHaving order by

13. SQL(cont’d) 必需同時使用兩個tableJOIN id name dep_id salary 00001 李小輝 A001
計算本書的出版社名字
**先看看這個小例子**
計算每個人部門所在地
SQL(cont’d)
必需同時使用兩個tableJOIN id
name
dep_id
salary
00001
李小輝
A001
10000
00002
連阿戰
8000
00003
陳阿扁
A002
11000
emp
dep_id
position
A001 台北
A002 高雄
dep

14. SQL(cont’d)
SELECT emp.id, dep.position FROM emp, dep WHERE emp.dep_id=dep.dep_id
JOIN: (inner join)
Join後會產生3*2=6筆記錄
經由where emp.dep_id=dep.dep_id過濾後，剩3筆
Example
Select stduent.id,student.name,class.classname,
class.tesacher from student,class where student.class=class.class

15. SQL(cont’d) 00001 李小輝 10000 A001 台北 A002 高雄 00002 連阿戰 8000 00003 陳阿扁
emp.id
emp.name
emp.salary
emp.dep_id
dep.dep_id
dep.position
00001
李小輝
10000
A001 台北
A002 高雄
00002
連阿戰
8000
00003
陳阿扁
11000

16. SQL(cont’d) 若欄位名重覆，可加上表格名做為區分 emp.dep_id, dep.dep_id…… 00001 李小輝 10000
emp.id
emp.name
emp.salary
emp.dep_id
dep.dep_id
dep.position
00001
李小輝
10000
A001 台北
00002
連阿戰
8000
00003
陳阿扁
11000
A002 高雄

17. SQL(cont’d)
SELECT Titles.title, Publishers.name, Publishers.address FROM Titles, Publishers WHERE Titles.PubId=Publishers.PubId
biblio.mdb

18. SQL(cont’d) INSERT:新增一筆資料 INSERT INTO Authors VALUES (2000,‘alex’,0)
INSERT INTO Authors(year,name,count)
VALUES (2000,‘alex’,0)
INSERT INTO Authors
select * from Authors_BK where….
(插入另一個表格的資料)

19. SQL(cont’d) INSERT INTO Student (id,name,phone)
VALUES (2006,‘alex’,NULL)
VALUES (2006,‘alex’,’’)

20. SQL(cont’d) DELETE:刪除一些資料 UPDATE:更新資料
DELETE FROM Authors WHERE author like ‘A%’
UPDATE:更新資料
UPDATE Authors
SET Author=‘Alex’ ,
count=7
WHERE au_id=20000

21. SQL(cont’d) http://www.1keydata.com/tw/sql/sql.html

22. 第十五章 資料庫III
Recordset

23. Recordset.AddNew
Recordset.Delete
Recordset.Edit
Recordset.Update

24. Recordset.MoveFirst
Recordset.MoveLast
Recordset.MoveNext
Recordset.MovePrevious

25. Recordset.Filter Recordset.Find Recordset.Bookmark
adSearchForward, adSearchBackward
Recordset.Bookmark

26. Dim bm as Variant
xxx.Recordset.MoveFirst
xxx.Recordset.Find “Sex = ‘True’”
While Not xxx.Recordset.EOF
xxx.Recordset.Find “Sex = ‘True’”, 1,_
adSearchForward, xxx.Recordset.Bookmark
Wend