Sql语句，查询效率

数据库：Sql Server

数据量：百万级

语句1：select count(*) from BF_BPRODUCT 

执行结果：

语句2：select * from BF_BPRODUCT where prodname like '医%'
语句3：select CPID, QYID, PRODNAME from BF_BPRODUCT where prodname like '医%'

 

语句4：select * from BF_BPRODUCT where prodname like '%医%'
语句5：select  CPID, QYID, PRODNAME from BF_BPRODUCT where prodname like '%医%'

 

语句6：select * from BF_BPRODUCT where charindex('医',prodname,1)>0
语句7：select  CPID, QYID, PRODNAME from BF_BPRODUCT where charindex('医',prodname,1)>0