資料庫常用語句
阿新 • • 發佈:2021-11-30
新建資料庫
USE [DataBase] GO IF EXISTS (SELECT * FROM sys.all_objects WHERE object_id = OBJECT_ID(N'[dbo].[table]') AND type IN ('U')) DROP TABLE [dbo].[table] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [table]( [Column1] [int] IDENTITY(1,1) NOT NULL, [Column2] [varchar](20) NOT NULL DEFAULT '無', CONSTRAINT [PK_table] PRIMARY KEY CLUSTERED ( [Column1] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO SET ANSI_PADDING OFF GO EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'第一列' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'[table]', @level2type=N'COLUMN',@level2name=N'[Column1]' GO EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'第二列' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'[table]', @level2type=N'COLUMN',@level2name=N'[Column2]' GO
新增列
Alter Table [table] Add [Column3] Decimal(18,2) null
修改列
Alter Table [table] Alter Column [Column3] Bit not null
刪除列
Alter Table [table] Drop Column [Column3]
新增值
INSERT [table] VALUES('第二列',1)
修改值
UPDATE [table] SET Column2='修改',Column3=0 where Column1=1
基礎查詢
SELECT 列名 FROM 表名 WHERE 判斷條件
左連線 LEFT JOIN(以左表為基礎表,兩表資料行不相等的情況下,左錶行多,則查詢出來的表,右表缺失部分為NULL,右表多出部分不顯示)
SELECT T1.列名,T2.列名 FROM 表名1 AS T1 LEFT JOIN 表名2 AS T2 ON T1.列名=T2.列名 WHERE 判斷條件
右連線 RIGHT JOIN(以右表為基礎表,兩表資料行不相等的情況下,右錶行多,則查詢出來的表,左表缺失部分為NULL,左表多出部分不顯示)
SELECT T1.列名,T2.列名 FROM 表名1 AS T1 RIGHT JOIN 表名2 AS T2 ON T1.列名=T2.列名 WHERE 判斷條件
內連線 INNER JOIN(只顯示兩表有共同資料行的部分,缺失部分都不顯示)
SELECT T1.列名,T2.列名 FROM 表名1 AS T1 INNER JOIN 表名2 AS T2 ON T1.列名=T2.列名 WHERE 判斷條件