product_code 如果有一列自动号列如: ID 则: select * from PRODUCT_TABLE T where [ID] = (Select max([id]) from PRODUCT_TABLE where T.product_code = product_code) select * from PRODUCT_TABLE T where [ID] in (Select top 1 [id] from PRODUCT_TABLE where T.product_code = product_code)
我这个表里没有自动编号的,product_code只是关键字之一,现在我想用 select * from PRODUCT_TABLE where plate='0000'order by PRODUCT_CODE,type DESC 来实现我要找的记录,原来是在程序中实现的,现在想优化
如果我有这样的记录
month plate proto_num subtitle product_code type
03031 0000 103250401 303250401100 1100310 303250402103195
03031 0000 103180601 303180601100 1100310 303180602103195
03031 0000 103195 103031042999 1100310 0
03031 0000 1030226801 00 1100311 0
02021 0000 102030361 302040361100 1100311 11100310
02021 0000 1030115801 00 1100312 502040361102040361
02121 0000 112260941 312260941100 1100312 11100310
02101 0000 110120771 310120771100 1100314 11100x01
02101 0000 110120772 310120771100 1100314 11100x01
我要取product_code不相同的记录,又怎么做?
也就是说要得到的结果有4个,如:
month plate proto_num subtitle product_code type
03031 0000 103250401 303250401100 1100310 303250402103195
02021 0000 102030361 302040361100 1100311 11100310
02021 0000 1030115801 00 1100312 502040361102040361
02101 0000 110120771 310120771100 1100314 11100x01怎么写?
select *
from PRODUCT_TABLE T
where [ID] = (Select max([id]) from PRODUCT_TABLE where T.product_code = product_code)
select *
from PRODUCT_TABLE T
where [ID] in (Select top 1 [id] from PRODUCT_TABLE where T.product_code = product_code)
select * from PRODUCT_TABLE where plate='0000'order by PRODUCT_CODE,type DESC
来实现我要找的记录,原来是在程序中实现的,现在想优化