Count rows per date in a date range - mysql

Question

I have been searching Google and SO for the last 25 min searching for how to do the following in MySQL.
I currently have the following query (Sent by PHP):
SELECT
COUNT(*),
`$db`.`crop`.`id` AS `crop`,
`$db`.`crop`.`harvest_date` AS `harvest_date`
FROM
`$db`.`crop`
WHERE
`$db`.`crop`.`harvest_date` BETWEEN $startDate AND $endDate
GROUP BY `$db`.`crop`.`harvest_date`
$startDate = 2012-01-01
$endDate = 2013-07-01
I am trying to find all the rows that have a harvest_date between start and end dates, and then count the number of rows that fall on the same date. However, I seem to be getting no results. The query doesn't fail, it just doesn't return anything. Can anyone point me in the right direction/tell me where I got it wrong?
EDIT: Found the problem. As Michael pointed out below, the dates were not getting passed as dates, but as numbers. I solved this by adding ' before and after startDate and endDate in the query.

Answer 1

MySQL expects date literals to be single-quoted strings like '2012-01-01' and '2013-07-01'.
Since you have not quoted your date literals which are PHP variables, PHP is actually interpreting them as arithmetic on integer values before it passes them into the query.
// You see this:
$startDate = 2012-01-01
$endDate = 2013-07-01
// PHP does this:
// 2012 - 1 - 1 = 2010
$startDate = 2010
// 2013 - 7 - 1 = 2005
$endDate = 2005
Your query ultimately uses this:
WHERE
`$db`.`crop`.`harvest_date` BETWEEN 2010 AND 2005
And MySQL will cast both of those integers to a DATE, which will return NULL.
mysql> SELECT CAST(2010 AS DATE);
+--------------------+
| CAST(2010 AS DATE) |
+--------------------+
| NULL |
+--------------------+
So the simple fix is:
$startDate = '2012-01-01';
$endDate = '2013-07-01';
And if you eventually convert this to a parameterized query, the correct quoting of placeholders would be handled for you.

Answer 2

To get the count between the given date range. Modify the query as
SELECT
COUNT(`$db`.`crop`.`id`),
FROM
`$db`.`crop`
WHERE
`$db`.`crop`.`harvest_date` BETWEEN $startDate AND $endDate
Grouping the result with "harvest_date" will determine the count for that particular date and group them.
example :
if the table is like
8-21-2013
8-21-2013
8-20-2013
then grouping will give
2
1
without grouping
3

Answer 3

I know this is an old post , but this worked for me
SELECT count(*),date(LSTUPDTIM),SUM(TOTAL) FROM order_table where LSTUPDTIM between '2018-01-20' and '2019-01-29' group by date(LSTUPDTIM) ;
,
my LSTUPDTIM is a TimeStamp which is why i had to use date()
which gave me an output like this
5 2019-01-25 500
2 2019-01-28 200
5 2019-01-29 500