使用内部联接时出现重复行

Question

$query = "SELECT a.value1,b.value2,a.category 
          FROM sale_villa as a 
          left join sale_land as b on a.area = b.area
          WHERE a.area='$area' 
          AND b.category BETWEEN '$from_date' AND '$to_date' ";

使用内连接时出现重复的行..

value1  value2
3000000     45000000
4900000     45000000
80000000    45000000
3000000     5000000
4900000     5000000
80000000    5000000
3000000     50000000
4900000     50000000
80000000    50000000

实际上我必须得到......

    value1      value2
    3000000     45000000
    4900000     45000000
    80000000    45000000


 sale_villa
    category

2015-02-01
2015-02-02
2015-02-03

sale_land
category

2015-02-01
2015-02-02
2015-02-03

2015-02-04

这是当前output和db result。

Answer 1

尝试INNER JOIN而不是左连接和GROUP BY a.value1