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LEFT ( character_expression , integer_expression )
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select left('my name is viwo',4)
my n
RIGHT ( character_expression , integer_expression )
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Àý:
select right('my name is viwo',4)
viwo
CAST ( expression AS data_type )
½«Ä³ÖÖÊý¾ÝÀàÐ͵ıí´ïʽÏÔʽת»»ÎªÁíÒ»ÖÖÊý¾ÝÀàÐÍ¡£CAST ºÍ CONVERT ÌṩÏàËÆµÄ¹¦ÄÜ¡£
Àý:
select cast(2 as varchar(10))+cast(11 as varchar(10))
211
CONVERT (data_type[(length)], expression [, style])
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Àý:
select convert(varchar,getdate(),112)
20070328
DATEADD ( datepart , number, date )
ÔÚÏòÖ¸¶¨ÈÕÆÚ¼ÓÉÏÒ»¶Îʱ¼äµÄ»ù´¡ÉÏ£¬·µ»ØÐ嵀 datetime Öµ¡£
Àý:
select dateadd(month,2,getdate())
2007-05-28 14:24:37.280
COALESCE ( expression [ ,...n ] )
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Àý:
select coalesce(null,null,0)
0
select coalesce(2,3,0)
2
CHARINDEX ( expression1 , expression2 [ , start_location ] )
·µ»Ø×Ö·û´®ÖÐÖ¸¶¨±í´ïʽµÄÆðʼλÖá£
Àý:
select charindex('ab','eabcd')
2
LTRIM ( character_expression )
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Àý:
select ltrim(' abc ')
abc
RTRIM ( character_expression )
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Àý:
select rtrim(' abc ')
abc
ROUND ( numeric_expression , length [ , function ] )
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select ROUND(748.585, 2)
748.590
FLOOR ( numeric_expression )
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Àý:
select floor(748.585)
748
CEILING ( numeric_expression )
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Àý:
select ceiling(748.585)
749
REPLACE ( 'string_expression1' , 'string_expression2' , 'string_expression3' )
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