mysql 3种 join

# inner join
# inner join并不以谁为基础,它只显示符合条件的记录.
select * from belle_dev.tbl_channel c inner join belle_dev.tbl_cp p on c.cp_id = p.id;

# left join
# left join 以左表为基础，若右表没有满足条件的数据则为空
select * from belle_dev.tbl_channel c left join belle_dev.tbl_cp p on c.cp_id = p.id;

# right join
# right  join 以右表为基础，若左表没有满足条件的数据则为空
select * from belle_dev.tbl_channel c right  join belle_dev.tbl_cp p on c.cp_id = p.id;