'' ' ''

 1 USE AdventureWorks2008R2;  
 2 GO  
 3 --CAST
 4 
 5 SELECT 'CAST' "CAST",
 6 CAST('1990-11-1' AS VARCHAR(10)) 转为字符串,
 7 CAST('1990-11-1' AS DATETIME) 转为日期
 8 
 9 --CONVERT
10 SELECT 'CONVERT' "CONVERT",
11 CONVERT(VARCHAR(10),'2999') 转为字符串,
12 CONVERT(INT,'2999') 转为整数
13 
14 --''
15 
16 select 'sb' 
17 select '''SB'''
18 SELECT '"SB"' --列名
19 SELECT  'it''s a pen'