Doing Math with SQL entries - mysql

Question

so I am trying to use MySQL to look at the values of our database, and spit out the sum of the values in a column between 2 date ranges. Currently I have gotten it to at least select the correct range of dates using the code:
SELECT fuelDate, SUM(gallons)
FROM fuel566243
WHERE fuelDate BETWEEN '2019-01-04' AND '2019-01-24'
GROUP BY fuelDate
ORDER BY fuelDate
The issue with this code, is in the SUM column that gets generated, it just displays all the values of the gallons column, but doesn't add them up. Is there a way to do this in SQL and output a result? Or is it easier to just use a foreach loop to cycle through the array and add the values using PHP?
When I run the code above, it gives me this output. How do I then get the sum of the gallons column shown below? Is there a way to do that in SQL? Or would I need to use a loop to add the values using PHP?
| fuelDate | Gallons | |
| 2019-01-04 | 53.8885 | |
| 2019-01-15 | 198.1700 | |
| 2019-01-17 | 167.2750 | |
| 2019-01-23 | 176.5620 | |
| 2019-01-24 | 181.0240 | |

Answer 1

The GROUP BY defines the rows that are being returned. You have included gallons as an aggregation key, so you have specified that you want a separate row for each value.
Simply remove the key from the GROUP BY and the SELECT:
SELECT fuelDate, SUM(gallons)
FROM fuel566243
WHERE fuelDate BETWEEN '2019-01-04' AND '2019-01-24'
GROUP BY fuelDate
ORDER BY fuelDate;
If you want the total during the period, then you want an aggregation with no GROUP BY:
SELECT SUM(gallons)
FROM fuel566243
WHERE fuelDate BETWEEN '2019-01-04' AND '2019-01-24';