宣告變數

SQL Server 入門

John MacKintosh

Instructor

變數

SELECT * 
FROM artist 
WHERE name = 'AC/DC';

現在把查詢改成另一位歌手：

SELECT * 
FROM artist 
WHERE name = 'U2';

為了避免重複，建立一個變數：

SELECT * 
FROM artist 
WHERE name = @my_artist;

DECLARE

DECLARE @

整數變數：

DECLARE @test_int INT

VARCHAR 變數：

DECLARE @my_artist VARCHAR(100)

SET

整數變數：

DECLARE @test_int INT

SET @test_int = 5

將值指定給 @my_artist：

DECLARE @my_artist  varchar(100)

SET @my_artist = 'AC/DC'

DECLARE @my_artist varchar(100)
DECLARE @my_album varchar(300);

SET @my_artist = 'AC/DC'
SET @my_album  = 'Let There Be Rock' ;

SELECT --
FROM --
WHERE artist = @my_artist
AND album = @my_album;

DECLARE @my_artist varchar(100)
DECLARE @my_album varchar(300);

SET @my_artist = 'U2'
SET @my_album  = 'Pop' ;

SELECT --
FROM --
WHERE artist = @my_artist
AND album = @my_album;

暫存資料表

SELECT 
  col1, 
  col2, 
  col3 INTO #my_temp_table
FROM my_existing_table 
WHERE 
  -- Conditions

#my_temp_table 會存在到連線或工作階段結束為止

-- 手動刪除資料表
DROP TABLE #my_temp_table

來宣告一些變數吧！

SQL Server 入門