尝试编写复杂查询以检索数据

时间：2013-11-06 04:59:13

标签： mysql sql

我正在尝试编写一个查询，告诉我Female每种颜色的数量。 

White - 2
Blue - 5
Green - 13

到目前为止，我有以下查询，我的一些尝试被注释掉了：

SELECT a.id AS aid, af.field_name AS aname, afv.field_value
FROM applications app, applicants a, application_fields af, application_fields_values afv, templates t, template_fields tf
WHERE a.application_id = app.id
AND af.application_id = app.id
AND afv.applicant_id = a.id
AND afv.application_field_id = af.id
#AND af.template_id = t.id
AND af.template_field_id = tf.id
AND t.id = tf.template_id
AND afv.created_at >= '2013-01-01' 
AND afv.created_at <= '2013-12-31' 
#AND af.field_name = 'Male' 
AND afv.field_value = 1
ORDER BY aid, aname
#GROUP BY aid, aNAME
#HAVING aname = 'Female';

目前此查询返回如下数据：

aid |  aname   | field_value
    4  Female   1
    4  White    1
    5  Green    1
    5  Female   1
    6  Female   1
    6  White    1
    7  Blue     1
    7  Female   1
    8  Female   1
    8  Blue     1
    9  Male     1
    9  Green    1

表格结构：

applications:
id

application_fields:
id
application_id
field_name

applications_fields_values:
id
application_field_id
applicant_id
field_value

template:
id

template_fields:
id
template_id

applicant:
id
application_id

示例数据：

application_fields
id | application_id | field_name |template_id | template_field_id
1  |        1       |     blue   |      1     |         1
2  |        1       |     green  |      1     |         2
3  |        1       |     female |      1     |         3

application_fields_values
id | application_field_id | applicant_id | field_value
4  |            1         |        1     |      1     
5  |            2         |        1     |      0     
6  |            3         |        1     |      1

templates
id |    name    |
1  | mytemplate |

template_fields
id | template_id | field_name |
1  |       1     |   blue
2  |       1     |   green
3  |       1     |   female

修改

我非常确定下面的查询能够获得我正在寻找的内容，但它的速度非常慢，我的最大表格行数不到30K。

查询

SELECT af.field_name AS aname, sum(afv.field_value) AS totals
    FROM applications app, applicants a, application_fields af, application_fields_values afv, templates t, template_fields tf
    WHERE a.application_id = app.id
    AND af.application_id = app.id
    AND afv.applicant_id = a.id
    AND afv.application_field_id = af.id
    AND af.template_field_id = tf.id
    AND t.id = tf.template_id
    AND afv.created_at >= '2013-01-01' 
    AND afv.created_at <= '2013-12-31' 
    AND afv.field_value = 1
    AND a.id IN (
        SELECT 
            a2.id
        FROM applications app2, applicants a2, application_fields af2, application_fields_values afv2, templates t2, template_fields tf2
        WHERE af2.application_id = app2.id
        AND afv2.applicant_id = a2.id
        AND afv2.application_field_id = af2.id
        AND af2.template_field_id = tf2.id
        AND t2.id = tf2.template_id
        AND afv2.created_at >= '2013-01-01' 
        AND afv2.created_at <= '2013-12-31' 
        #AND af2.field_name = 'Male' 
        AND af2.field_name = 'Female'
        AND afv2.field_value = 1
    )
    GROUP BY aname;

产生结果：

aname | totals
Green    2
Black    27
Blue     5

4 个答案:

答案 0 :(得分：4)

SELECT f1.field_name, count(*) as total
  FROM application_fields f1
  JOIN applications_fields_values v1
    ON v1.application_field_id = f1.id
  JOIN applications_fields_values v2
    ON v1.applicant_id = v2.applicant_id
  JOIN applications_fields f2
    ON v2.application_field_id = f2.id
 WHERE v1.field_value = 1
   AND v2.field_value = 1
   AND f2.field_name = 'Female'
   AND f1.field_name != 'Female'
   AND f1.created_at BETWEEN '2013-01-01' AND '2013-12-31' 
 GROUP BY f1.field_name

除非您有其他要求，否则您似乎无需引用表格templates，template_fields，applications或applicant来解决您的问题。此外，您还不清楚如何识别哪种application_fields代表颜色。如果您有更多相关信息，可能会添加一些条件。

答案 1 :(得分：0)

查询看起来很好，只需在WHERE子句中添加条件，如果您希望过滤掉基于分组的结果，则应在HAVING内添加

试试这个

SELECT 
    af.field_name AS aname, 
    count(afv.field_value) as totals
FROM 
    applications app, 
    applicants a, 
    application_fields af, 
    application_fields_values afv, 
    templates t, 
    template_fields tf
WHERE 
    a.application_id = app.id
    AND af.application_id = app.id
    AND afv.applicant_id = a.id
    AND afv.application_field_id = af.id
    #AND af.template_id = t.id
    AND af.template_field_id = tf.id
    AND t.id = tf.template_id
    AND afv.created_at >= '2013-01-01' 
    AND afv.created_at <= '2013-12-31' 
    #AND af.field_name = 'Male' 
    AND afv.field_value = 1
    AND aname = 'Female'
ORDER BY 
    aname
GROUP BY 
    aNAME

答案 2 :(得分：0)

尝试使用EXISTS函数代替IN 

SELECT af.field_name AS aname, sum(afv.field_value) AS totals
FROM applications app, applicants a, application_fields af, application_fields_values afv, templates t, template_fields tf
WHERE a.application_id = app.id
AND af.application_id = app.id
AND afv.applicant_id = a.id
AND afv.application_field_id = af.id
AND af.template_field_id = tf.id
AND t.id = tf.template_id
AND afv.created_at >= '2013-01-01' 
AND afv.created_at <= '2013-12-31' 
AND afv.field_value = 1
AND EXISTS (
    SELECT 
        1
    FROM applications app2, applicants a2, application_fields af2, application_fields_values afv2, templates t2, template_fields tf2
    WHERE af2.application_id = app2.id
    AND afv2.applicant_id = a2.id
    AND afv2.application_field_id = af2.id
    AND af2.template_field_id = tf2.id
    AND t2.id = tf2.template_id
    AND afv2.created_at >= '2013-01-01' 
    AND afv2.created_at <= '2013-12-31' 
    #AND af2.field_name = 'Male' 
    AND af2.field_name = 'Female'
    AND afv2.field_value = 1
    AND a.id = a2.id    -- add this condition
)
GROUP BY aname;

来源：http://dev.mysql.com/doc/refman/5.5/en/optimizing-subqueries.html

注意：根据几个条件，这个修改可能会更快或更慢，如果它在该（源）页面的底部考虑几个条件则会更慢。

答案 3 :(得分：0)

您应该考虑更清晰的设计。似乎有不同的问题。

例如，通过使用template和template_fields值（以及提供的示例数据），我可以猜测[应用程序字段]派生自[te​​mplates]，只要应用程序只有一个模板。在这种情况下，您可以通过multi_ to-multi表设计application_fields_values，如下所示：

applications:                   
id | template_id

application_fields_values:      
application_id | template_field_id | field_value

application fields: redundant

template information derived from template_fields

这适用于[应用程序字段]应该存在与否（即如果部分遵循模板字段集），     或者如果一组模板是强制性的。

通常，您的表似乎有多余的引用。

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