Question

我正在尝试确定两个表之间按州和城市分组的城市人口变化，如下所示：

**TABLE 1**                          **TABLE 2**
NY    New York    10,000             NY    New York    -3000
NY    Syracuse     5,000             NY    Syracuse     5000
PA    Phila       12,000             PA    Phila        1000
PA    Erie        11,000             PA    Erie         4000

我使用的查询如下：

SELECT Table1.State, Table1.City, SUMtable1.populationsum-Nz(SUMtable2.populationsum,0) AS Total
FROM (SELECT SUM(table1.populationchange) AS popsum, table1.State
      FROM Table1
      GROUP BY table1.State, table1.City) AS SUMtable1 
LEFT JOIN (SELECT SUM(table2.populationchange) AS rsum, table2.State
           FROM table2
           GROUP BY table2.State, table2.City)  AS SUMtable2 
ON SUMtable1.State= SUMtable2.State;

但是，这只能给我这个：

**RESULT**                                  
NY                 7000
NY                10000
PA                13000
PA                15000

我需要它才能返回城市。此时，查询提示我输入城市的参数值。将它留空并按下输入会得到我的结果。我该如何完成此查询？

Answer 1

City不是FROM查询的一部分。

SELECT State,City, sum(possum) AS Total
FROM ((
      SELECT SUM(table1.populationchange) AS popsum, table1.State as state, 
Table1.City as city
  FROM Table1
  GROUP BY table1.State, table1.City)  
Union All (
         SELECT SUM(table2.populationchange) AS rsum, table2.State as state , 
Table2.City as city
       FROM table2
       GROUP BY table2.State, table2.City) ) 
Group by state,city

Answer 2

样本表的相同情况：

        create table #temp1(c varchar(100),s varchar(100), p int);
    create table #temp2(c varchar(100),s varchar(100), p int);
    Insert into #temp1(c,s,p) values('ny','syc',10)
    Insert into #temp1(c,s,p) values('ny','ny',10)
    Insert into #temp1(c,s,p) values('Nc','ra',10)
    Insert into #temp1(c,s,p) values('Ns','char',10)
    Insert into #temp2(c,s,p) values('ny','syc',10)
    Insert into #temp2(c,s,p) values('ny','ny',10)
    Insert into #temp2(c,s,p) values('Nc','ra',10)
    Insert into #temp2(c,s,p) values('Ns','char',10)

    select result.s,result.c,sum(p) as total  from (
    select * from #temp1 union all select * from #temp2) as result group by result.c,result.s

确切查询：

    select res.state,res.city,sum(res.popultationchange) as totalchange 
     from(
    select * from Table1 union all select * from Table2
    ) as res group by res.state,res.city

希望这是你所需要的！

（简单）SQL不返回所需的列。半工作查询（访问）

2 个答案: