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我有一个简单的查询：

SELECT sds.district_id,detail.year, detail.race, SUM(count)
FROM school_data_race_ethnicity_raw as detail
INNER JOIN school_data_schools as sds USING (school_id)
GROUP BY district_id, year, race

样本结果集：

| 68080104    | 2009 | Multiracial     |          0 |
| 68080104    | 2009 | White           |        847 |
| 68080104    | 2010 | American Indian |          1 |
| 68080104    | 2010 | Asian           |          4 |
| 68080104    | 2010 | Black           |         17 |
| 68080104    | 2010 | Hispanic        |          4 |
| 68080104    | 2010 | Multiracial     |          2 |
| 68080104    | 2010 | White           |        823 |
| 68080104    | 2011 | American Indian |          4 |
| 68080104    | 2011 | Asian           |          4 |
| 68080104    | 2011 | Black           |          9 |
| 68080104    | 2011 | Hispanic        |         10 |
| 68080104    | 2011 | Multiracial     |         24 |
| 68080104    | 2011 | White           |        767 |
+-------------+------+-----------------+------------+

我想添加一个名为 total 的第 5 列，它显示给定年份和地区总人口的总和。例如，如果我在 2011 年在 68080104 区，那么总数将是 (4+4+9+10+24+767)。我需要它作为此查询中的另一列。它还需要快速。（不到 10 秒）。我正在努力解决如何做到这一点而不影响速度和数据。

4

3 回答 3

2

您需要为此创建一个单独的查询并将其与原始查询连接。试试这个，

SELECT a.*, b.totalCount
FROM
    (
        SELECT sds.district_id,detail.year, detail.race, SUM(count)
        FROM    school_data_race_ethnicity_raw as detail
                    INNER JOIN school_data_schools as sds 
                        USING (school_id)
        GROUP BY district_id, year, race
    )   a INNER JOIN
    (
        SELECT sds.district_id,detail.year, SUM(count) totalCount
        FROM    school_data_race_ethnicity_raw as detail
                    INNER JOIN school_data_schools as sds 
                        USING (school_id)
        GROUP BY district_id, year
    )   b ON a.district_id = b.district_id AND
            a.year = b.year
于 2012-09-06T15:11:32.577 回答
1

使用 WITH ROLLUP

SELECT sds.district_id,detail.year, detail.race, SUM(count)
FROM school_data_race_ethnicity_raw as detail
INNER JOIN school_data_schools as sds USING (school_id)
GROUP BY district_id, year, race WITH ROLLUP
于 2012-09-06T15:07:51.253 回答
0

在 MySQL 中，要获取同一行上的数据，您几乎必须将其作为连接来执行：

select t.*, t2.cnt as TotalDistrictYear
from (SELECT sds.district_id,detail.year, detail.race, SUM(count) as cnt
      FROM school_data_race_ethnicity_raw as detail INNER JOIN
           school_data_schools as sds USING (school_id)
      GROUP BY district_id, year, race
     ) t join
    (SELECT sds.district_id,detail.year,SUM(count) as cnt
      FROM school_data_race_ethnicity_raw as detail INNER JOIN
           school_data_schools as sds USING (school_id)
      GROUP BY district_id, year
     ) t2
     on t.district_id = t2.district_id and
        t.year = t2.year
于 2012-09-06T15:12:14.517 回答