Delphi 与SQL编程
时间：2021-07-01 10:21:17
帮助过：10人阅读
Unit1;
interface
uses
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;
Button2: TButton;
Button3: TButton;
Button4: TButton;
Button5: TButton;
Button6: TButton;
Button7: TButton;
Button8: TButton;
Button9: TButton;
Button10: TButton;
Button11: TButton;
Button12: TButton;
Button13: TButton;
Button14: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
procedure Button6Click(Sender: TObject);
procedure Button7Click(Sender: TObject);
procedure Button8Click(Sender: TObject);
procedure Button9Click(Sender: TObject);
procedure Button10Click(Sender: TObject);
procedure Button11Click(Sender: TObject);
procedure Button12Click(Sender: TObject);
procedure Button13Click(Sender: TObject);
procedure Button14Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
//country 表中 Area<200000 的记录
procedure TForm1.Button1Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Area<200000‘;
Open;
end;
end;
//country 表中 Continent="South America" 的记录; 字符串值应该在引号中(单引号、双引号均可).
procedure TForm1.Button2Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Continent="South America"‘;
Open;
end;
end;
//country 表中 Name="Cuba" 或者 Name="Peru" 的记录
procedure TForm1.Button3Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name="Cuba" or Name="Peru"‘;
Open;
end;
end;
//country 表中 Continent="South America" 并且 Area>1000000 的记录
procedure TForm1.Button4Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Continent="South America" and Area>1000000‘;
Open;
end;
end;
//country 表中 Name 是 c 开头的记录; 其中的 % 表示任意字符串
procedure TForm1.Button5Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "c%"‘;
Open;
end;
end;
//country 表中 Name 是 b 或 c 开头的记录; 可以用 "," 隔开更多条件
procedure TForm1.Button6Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "[b,c]%"‘;
Open;
end;
end;
//country 表中 Name 是 a 或 b 或 c 开头的记录
procedure TForm1.Button7Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "[a-c]%"‘;
Open;
end;
end;
//country 表中 Name 不是 a 或 b 或 c 或 m 开头的记录
procedure TForm1.Button8Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name NOT LIKE "[a-c,m]%"‘;
Open;
end;
end;
//country 表中 Name 不是 a 或 b 或 c 开头的记录
procedure TForm1.Button9Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name NOT LIKE "[a-c]%"‘;
Open;
end;
end;
//country 表中 Name 包含 er 的记录
procedure TForm1.Button10Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "%er%"‘;
Open;
end;
end;
//country 表中 Name 包含空格的记录
procedure TForm1.Button11Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "% %"‘;
Open;
end;
end;
//country 表中 Name 第二个字符任意, 但第一字符是 p、第三字符是 r 的记录; "_" 表示任意字符
procedure TForm1.Button12Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "p_r%"‘;
Open;
end;
end;
//country 表中 Name 是 4 个字符的记录
procedure TForm1.Button13Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "____"‘;
Open;
end;
end;
//country 表中 Name 是 4 个字符, 但最后是 a 结尾的记录
procedure TForm1.Button14Click(Sender: TObject);
begin
with ADODataSet1
do begin
Close;
CommandText :=
‘SELECT * FROM country WHERE Name LIKE "___a"‘;
Open;
end;
end;
procedure TForm1.FormCreate(Sender: TObject);
var
mdbFile: string;
begin
mdbFile := GetEnvironmentVariable(
‘COMMONPROGRAMFILES‘);
mdbFile := mdbFile +
‘\CodeGear Shared\Data\dbdemos.mdb‘;
ADODataSet1.ConnectionString :=
‘Provider=Microsoft.Jet.OLEDB.4.0;Data Source=‘ +
mdbFile +
‘;Persist Security Info=False‘;
DBGrid1.DataSource :=
DataSource1;
DataSource1.DataSet :=
ADODataSet1;
end;
end.
View Code
怎样用SQL语句查询一个数据库中的所有表
SQL : select * from information_schema.tables
ORACLE: select table_name from user_tables
ACCESS: select name from MSysObjects where type=1 and flags=0
Delphi 与SQL编程
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