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[¤À¨É] SqlServerCentral¨C¤é¤@ÃD¤¤¤å¾ã²z

¥»©«³Ì«á¥Ñ kimbal ©ó 2010-8-30 23:57 ½s¿è

T-SQL ½g

2010-08-04 null »P coalesce
isnull, coalese ªº¤p¤À§O
  1. DECLARE @STR VARCHAR(3)
  2. SET @STR=NULL
  3. SELECT ISNULL(@STR,'GIVEN STRING IS NULL')
  4. SELECT COALESCE(@STR,'GIVEN STRING IS NULL')
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ISNULL·|¥ý¬d¬Ý@STRÃþ«¬. ¦ýCOALESE ´N¤£·|


2010-08-30 '' »P 0
  1. create table  #temp(id INT, code nvarchar(2))
  2. insert into #tempselect 1, '0' UNION
  3. select 2, '1' UNION
  4. select 3, '0' UNION
  5. select 4,'22' UNION
  6. select 5,'0'
  7. update #temp set code = '' where code = '0'
  8. select * from #temp where code = 0
  9. drop table #temp
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'' = 0
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