使用单个mySQL查询检索多个“系列”数据

Question

Is there a way to combine these two queries into a single one so that I can retrieve two data "series" for charting purposes while still maintaining the relationship for a single date?

SELECT 
        COUNT(j.id) AS power_count, jd.ber_rcvd 
    FROM
        jobs j 
        INNER JOIN job_dates jd 
            ON jd.job_id = j.id 
    WHERE j.tech = 7 AND jd.ber_rcvd != '0000-00-00' GROUP BY jd.ber_rcvd;
SELECT 
        COUNT(j.id) AS transport_count, jd.ber_rcvd 
    FROM
        jobs j 
        INNER JOIN job_dates jd 
            ON jd.job_id = j.id 
    WHERE j.tech = 1 AND jd.ber_rcvd != '0000-00-00' GROUP BY jd.ber_rcvd;

What I am looking for is output like this:

power_count | transport_count | ber_rcvd

    11      |          3      | 2013-03-01

     7      |          1      | 2013-03-02

Answer 1

Use the GROUP BY function:

SELECT j.tech, COUNT( j.id ) AS ber_count 
FROM job j
    INNER JOIN job_dates jd ON jd.job_id = j.id
WHERE j.tech IN ( 7, 1 )
GROUP BY j.tech;

That should give you two rows, one for tech=1, one for tech=7. And when you use the GROUP BY function, the COUNT() applies to each grouping.

In response to updated question, try this:

SELECT COUNT( IF(j.tech=7,1,NULL)) AS power_count, COUNT( IF( j.tech = 1, 1, NULL )) AS transport_count, jd.ber_rcvd
FROM
    jobs j 
    INNER JOIN job_dates jd 
        ON jd.job_id = j.id 
WHERE j.tech IN ( 1, 7 ) AND jd.ber_rcvd != '0000-00-00' 
GROUP BY jd.ber_rcvd;

If that is not it, please post some sample data for us to work with.

Answer 2

With UNION ALL it will look like

SELECT COUNT(j.id) AS ber_count, jd.ber_rcvd 
  FROM jobs j 
       INNER JOIN job_dates jd 
               ON jd.job_id = j.id 
 WHERE j.tech = 7
 UNION ALL
SELECT COUNT(j.id) AS ber_count, jd.ber_rcvd 
  FROM jobs j 
       INNER JOIN job_dates jd 
               ON jd.job_id = j.id 
 WHERE j.tech = 1

But GROUP BY is a better approach as @Seth suggested