[MSSQL] 숫자 ->문자 / 문자 ->숫자 변환 ( Convert / Cast )

1. Convert 

 

 1) 문자 -> 숫자 변환

 

CONVERT( [숫자형], [값] )

 

예)

 

SELECT   CONVERT(int, '3') 
           , CONVERT(float, '3.14') 
           , CONVERT(numeric, '3.141592') 
           , CONVERT(numeric(5,4), '3.141592') 
           , CONVERT(decimal(5,4), '3.141592')

 

 

 

 

 

2)숫자 -> 문자 변환

 

CONVERT( [문자형], [값] ,[스타일])

※ 스타일은 생략가능 

 

예) CONVERT(CHAR(8), 1999222, 20)   

 

 

SELECT  CONVERT(CHAR(10), 123456789) as 'CHAR' ,
           CONVERT(varchar(10), 123456789) as 'varchar',
           CONVERT(nchar, 1) as 'nchar'

 

2. Cast 

 

1)문자 -> 숫자 변환

 

  CAST('[값]' AS [숫자형])

 

예)

SELECT  CAST('3' AS INT) as 'int',
           CAST('3.14' AS float) as 'float',
           CAST('3.141592' AS numeric(5,4)) as 'numeric',
           CAST('3.141592' AS decimal(5,4))  as 'decimal'

 

 

2)숫자 -> 문자 변환

 

 CAST([값] AS [문자형])

 

예)

select      CAST(123456789 AS CHAR(10)) as 'CHAR' ,
             CAST(123456789 AS varchar(10)) as 'varchar',
             CAST(1 AS nchar) as 'nchar'