sql语句，选第一条数据

几个常用数据库的写法如下：

1、mssql 数据库

select top 1  * from table

2、Oracle数据库

select * from table  where rownum < 2

3、MySQL数据库：

select * from table  limit 0, 1

（这里keyword limit startid，rownum是这样的：表示从startid + 1行开始，一共查询rownum条记录。

SELECT top 1 company_id,bargain_man,bargain_type,bargain_time FROM bargain(数据库表) WHERE bargain_time<时间1 and bargain_time > 时间2

SELECT top 1 company_id,bargain_man,bargain_time
from (
select company_id,bargain_man,bargain_time FROM info_net
union all
select company_id,bargain_man,bargain_time FROM info_ad
union all
select company_id,bargain_man,bargain_time FROM info_train
)
WHERE bargain_time<时间1 and bargain_time > 时间2

SELECT count(*) FROM bargain(数据库表) WHERE bargain_time<时间1 and bargain_time > 时间2

不懂