SQL数据库编程 - 随笔分类 - [墨白]

SQL 语句 - Insert、Update、Delete

摘要：unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) DBGrid1: TDBGrid; DataSource1: TDataSource; ADOConnection1: TADOConnection; ADODataSet1: TADODataSet; ADOCommand1: TAD 阅读全文

posted @ 2011-07-01 23:44 [墨白] 阅读(265) 评论(0) 推荐(0)

SQL 语句 - Select(9): 其他

摘要：//只要前五条记录procedure TForm1.Button1Click(Sender: TObject);begin with ADODataSet1 do begin Close; CommandText := 'SELECT TOP 5 * FROM country'; Open; end;end;//去除重复procedure TForm1.Button2Click(Sender: TObject);begin with ADODataSet1 do begin Close; CommandText := 'SELECT DISTINCTROW * FROM 阅读全文

posted @ 2011-07-01 23:42 [墨白] 阅读(104) 评论(0) 推荐(0)

SQL 语句 - Select(8): 分组条件

摘要：代码文件: //分组条件可以是 Whereprocedure TForm1.Button1Click(Sender: TObject);begin with ADODataSet1 do begin Close; CommandText := 'SELECT Continent, AVG(Area) AS 平均面积 ' + 'FROM country WHERE Continent="South America" GROUP BY Continent'; Open; end;end;//也可以是 Havingprocedure TForm1. 阅读全文

posted @ 2011-07-01 23:41 [墨白] 阅读(332) 评论(0) 推荐(0)

SQL 语句 - Select(7): 分组统计之 Avg()、Sum()、Max()、Min()、Count()

摘要：Group By本来 Group By 也可以根据多个字段分组("," 隔开), 但这个例子只有 Continent 字段适合分组, 也只有 Area、Population 字段适合统计. 本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) 阅读全文

posted @ 2011-07-01 23:40 [墨白] 阅读(277) 评论(0) 推荐(0)

SQL 语句 - Select(6): 字段运算

摘要：本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) DBGrid1: TDBGrid; DataSource1: TDataSource; ADODataSet1: TADODataSet; Panel1: TPanel; Button1: TButton; p 阅读全文

posted @ 2011-07-01 23:39 [墨白] 阅读(273) 评论(0) 推荐(0)

SQL 语句 - Select(5): 字段别名

摘要：本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) DBGrid1: TDBGrid; DataSource1: TDataSource; ADODataSet1: TADODataSet; Panel1: TPanel; Button1: TButton; B 阅读全文

posted @ 2011-07-01 23:38 [墨白] 阅读(247) 评论(0) 推荐(0)

SQL 语句 - Select(4): 排序

摘要：Order By Asc|Desc 本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) DBGrid1: TDBGrid; DataSource1: TDataSource; ADODataSet1: TADODataSet; Panel1: TPanel; B 阅读全文

posted @ 2011-07-01 23:36 [墨白] 阅读(190) 评论(0) 推荐(0)

SQL 语句 - Select(3): 条件查询与模糊查询

摘要：Where 用来指定查询条件;Like 和 Not Like 来指定模糊条件;模糊条件中:_ 表示任一字符;% 表示任一字符串;[] 表示一个集合. 本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) DBGrid1: TDBGrid; DataSource1: 阅读全文

posted @ 2011-07-01 23:34 [墨白] 阅读(818) 评论(0) 推荐(0)

SQL 语句 - Select(2): 指定表中的字段

摘要：//选择 country 表中的 Name 字段SELECT Name FROM country//选择 country 表中的 Name、Area 和 Population 字段SELECT Name,Area,Population FROM country{多个字段时, 字段名是用 "," 隔开的}本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtr 阅读全文

posted @ 2011-07-01 23:33 [墨白] 阅读(420) 评论(0) 推荐(0)

SQL 语句 - Select(1): 指定表

摘要：//选择 country 表中的所有字段SELECT * FROM country{虽然 SQL 并不区分大小写, 但应习惯把关键字大写}本例效果图: 代码文件: unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;type TForm1 = class(TForm) Panel1: TPanel; Button1: TButton; Bu 阅读全文

posted @ 2011-07-01 23:29 [墨白] 阅读(428) 评论(0) 推荐(0)

随笔分类 - SQL数据库编程