数据库查询后几条数据Mysql Oracle SQLServer

（1）Mysql查询后几条数据
a：mysql有自增主键
select * from table order by tss desc limit 2
b：mysql没有自增主键
select count(*) from table
select * from kj_commondate_jyck limit table数据量-1,1
（2）Oracle查询后几条数据
select * from (select t.*,rownum n from fi_kj_log t) where n > (select count(1)-10 from fi_kj_log) and n <= (select count(1) from fi_kj_log )
（3）SQLServer查询后几条数据
a：SQLServer有自增主键
SELECT TOP N * FROM TABLE   按照自增id进行降序desc
select pk_recbill from (select top 10  * from ar_recitem order by ts desc)a

b：SQLServer没有自增主键