存储过程中变量为空应当如何？

SET @sql_word= 'insert into '+@ResultTable +'
select distinct EXITSTATION,11,exitdate,RECORDTYPE,vehicleclass,totaltoll
from '+@BaseTable+' 
where EXITSTATION = '+@Station+'
GROUP BY exitdate,EXITSTATION,RECORDTYPE,vehicleclass,totaltoll
order by EXITSTATION,exitdate,RECORDTYPE,vehicleclass,totaltoll'
print(@sql_word)
exec(@sql_word)

如果我的@Station 为空，这个代码便会报错，请问怎样表现才会让我@Station 变量为空时跳过这行？
[解决办法]

if @Station <>''
begin
SET @sql_word= 'insert into '+@ResultTable +'
                            select distinct EXITSTATION,11,exitdate,RECORDTYPE,vehicleclass,totaltoll
                            from '+@BaseTable+' 
                            where EXITSTATION = '+@Station+'
                            GROUP BY exitdate,EXITSTATION,RECORDTYPE,vehicleclass,totaltoll
                            order by EXITSTATION,exitdate,RECORDTYPE,vehicleclass,totaltoll'
end

就这样改。再试试
[解决办法]
try this,

SET @sql_word= 'insert into '+@ResultTable
             +' select distinct EXITSTATION,11,exitdate,RECORDTYPE,vehicleclass,totaltoll '
             +' from '+@BaseTable 
             +' where 1=1 '+case when @Station<>'' then ' and EXITSTATION='''+@Station+''' ' else '' end 
 
             +' GROUP BY exitdate,EXITSTATION,RECORDTYPE,vehicleclass,totaltoll '
             +' order by EXITSTATION,exitdate,RECORDTYPE,vehicleclass,totaltoll '

print(@sql_word)                
exec(@sql_word)

[解决办法]

引用:

Quote: 引用:

SET @sql_word= 'insert into '+@ResultTable +'
                            select distinct EXITSTATION,11,exitdate,RECORDTYPE,vehicleclass,totaltoll
                            from '+@BaseTable+' 
                            where EXITSTATION = '+ ISNULL(@Station,'EXITSTATION') +'
                            GROUP BY exitdate,EXITSTATION,RECORDTYPE,vehicleclass,totaltoll
                            order by EXITSTATION,exitdate,RECORDTYPE,vehicleclass,totaltoll'
print(@sql_word)

似乎不行：
insert into Plan200902
select distinct EXITSTATION,11,exitdate,RECORDTYPE,vehicleclass,totaltoll
from AUDIT..exit2009020050303
where EXITSTATION =
GROUP BY exitdate,EXITSTATION,RECORDTYPE,vehicleclass,totaltoll
order by EXITSTATION,exitdate,RECORDTYPE,vehicleclass,totaltoll
消息 156，级别 15，状态 1，第 5 行
关键字 'GROUP' 附近有语法错误。

你这个不是null而是等于空的字符串。。。

改一下就可以了

SET @sql_word= 'insert into '+@ResultTable +'
                            select distinct EXITSTATION,11,exitdate,RECORDTYPE,vehicleclass,totaltoll
                            from '+@BaseTable+'  
 
                            where EXITSTATION = '+ CASE ISNULL(@Station,'') 
   WHEN '' THEN 'EXITSTATION' 
   ELSE @Station END +'
                            GROUP BY exitdate,EXITSTATION,RECORDTYPE,vehicleclass,totaltoll
                            order by EXITSTATION,exitdate,RECORDTYPE,vehicleclass,totaltoll'