多表sqlite的连接查询问题

Question

朋友们好，我有如下四张表

property_master --> "p_id" , "p_name" , "p_address" , "p_city" , "p_state" ,"r_id"

property_unit -->"unit_id"   , "p_id"  , "unit_name"   ,"r_id"

unit_info -->    "unit_info_id"   ,"unit_id" INTEGER,"p_id"   ,"p_bathroom"  ,"p_bedroom"  ,"p_size"  ,"p_rent"  ,"p_isrent"  ,"u_note" ,"r_id" 

tanant_master -->  "t_id"   , "t_name"  ,"t_cell_no"  ,"t_phone_no"  ,"t_mail"  ,"t_deposit"   ,"r_id"

property_assign-->  "t_assign_id"   , "unit_info_id"  ,  "t_id"  , "t_start_date"  , "t_end_date"  , "  t_rent_due_day"  , "t_lease_alert"  , "t_status"  ,"r_id"

我的查询如下

Select p_name As "Property",
p_id AS "PID",
(Select Count(unit_id) from property_unit where   property_master.p_id=property_unit.p_id )As "UnitCount",
(Select Count(unit_info_id) from unit_info where unit_info.unit_info_id=property_assign.unit_info_id )As "TenantCount"
From property_master  ,property_assign Group by property_master.p_id

我需要总租户数属性wise 但是当我运行上面的查询它只给我第一个属性租户数所有属性知道我怎么能解决了吗？

Answer 1

尝试这样的事情：

select a.PID,
       MAX(a.Property) as "Property",
       COUNT(a.unit_id) as "UnitCount",
       SUM(a.TenantCount) as "TenantCount"
  from (
        select property_master.p_id as "PID",
               MAX(property_master.p_name) as  "Property",
               property_unit.unit_id,
               COUNT(property_assign.t_id) as "TenantCount"
          from property_master
          JOIN property_unit ON property_master.p_id = property_unit.p_id
          JOIN unit_info ON unit_info.unit_id = property_unit.unit_id
          JOIN property_assign ON unit_info.unit_info_id = property_assign.unit_info_id 
         group by property_master.p_id, property_unit.unit_id
       ) a,
 group by a.PID

注意 1 您可能需要使用 LEFT OUTER JOIN 而不是 JOIN 取决于您的数据结构（可以 property_assign 为空或不?)

注2.抱歉，我没法测试。你应该自己做。

多表sqlite的连接查询问题

Issue in join query of multiple tables sqlite

mysql

sqlite

android

left-join