PHP and Mysql, avoid multiple loop queries

I have a table myTable that looks like this:

+-------+-------+--------+------------+
| Id    | Agent | Qualif |    Date    |
+-------+-------+--------+------------+
|     1 | A     | Q1     | 2019-05-11 |
|     2 | B     | Q2     | 2019-05-11 |
|     3 | C     | Q1     | 2019-05-12 |
|     4 | A     | Q1     | 2019-05-11 |
|     5 | A     | Q2     | 2019-05-11 |
+-------+-------+--------+------------+

for a given date range, I need to show count of rows per date, per agent, and count(rows)-count(qualif = Q1) / count(rows)

To explain more, the way I do it on my PHP page is query first for:

SELECT date, Agent, count(*) as tot
     FROM myTable
     WHERE date between d1 and d2
     group by date, agent

And when looping through the result for each agent and date, I query for:

SELECT count(*) as totQ1 FROM my table WHERE date='somedate' and agent='someagent' and qualif='Q1'

The expected result for a period between ‘2019-05-11’ AND ‘2019-05-12’

+------------+--------+-----+-----------+
|   date     | Agent  | tot | division  |
+------------+--------+-----+-----------+
| 2019-05-11 | A      |   3 | 2/3       |
| 2019-05-11 | B      |   1 | 1         |
| 2019-05-12 | C      |   1 | 1         |
+------------+--------+-----+-----------+

taking into consideration if tot=0;

Is there any way I can combine all of this into one query so I don’t have to query multiple times for each date and agent?

Answer

You could use conditional SUM(), as in:

SELECT
  date, 
  Agent, 
  count(*) as tot,
  sum(case when Qualif = 'Q1' then 1 else 0 end) / count(*) as division
FROM myTable
WHERE date between d1 and d2
GROUP BY date, agent

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Answer