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Visual Basic 程式設計

Visual Basic 程式設計. 講師：戴志華 hana@arbor.ee.ntu.edu.tw 國立台灣大學電機工程研究所. 第十五章 資料庫 III. SQL. SQL. ORDER BY: 排序 SELECT au_id, author FROM authors ORDER BY au_id [ ASC | DESC ]. 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.

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Visual Basic 程式設計

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  1. Visual Basic 程式設計 講師：戴志華 hana@arbor.ee.ntu.edu.tw 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 ORDERBY 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. 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

  9. Examples (cont’d) • Select count(id) from Employee_TBL 6 • Select count(pager) from Employee_TBL 2 • Select count(*) from Employee_TBL 6 • 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. 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. 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 emp dep

  14. SQL(cont’d) • SELECT emp.id, dep.position FROM emp, depWHERE 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)

  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……

  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) • INSERT INTO Student (id,name,phone) VALUES (2006,‘alex’,’’)

  20. SQL(cont’d) • DELETE:刪除一些資料 • 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 • http://www.geocities.com/SiliconValley/Vista/2207/sql1.html • http://www.w3schools.com/sql/default.asp

  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 • Find (條件設定式, 略過資料筆數, 搜尋方向, 搜尋起始處) • 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

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