Check if multiple dates are the same in foreach

Question

I have an "Events" table in MySQL : EventsDate('id','event','start_date','end_date')

I'd like to check if multiple events have the same start date to show it differently in my HTML template. My SQL request is : SELECT * FROM EVENTSDATE where event='$id' and start_date>='$today' order by start_date asc

Now my foreach :

foreach ($upcomingDates as $value) { //$upcoming is the array with my sql request

        }

How can I say : "if you find two rows with the same start_date, echo something"

the way I would do it is add each date to an array as a key, then use array_key_exists (http://www.w3schools.com/php/func_array_key_exists.asp) to see if it is already in the array prior to adding it. — Marshall Tigerus, Jun 14 '16 at 13:51
You have to run another sql-query to select duplicates with the same start date. — Sergey Nazarenko, Jun 14 '16 at 13:51
If you're searching by id, why would you have multiple rows in your result? — Patrick Q, Jun 14 '16 at 14:03

Peter · Accepted Answer · 2016-06-14T14:28:23.233

1

I have a slightly different approach.

// Array to contain all values
$container = array();

// Loop through your existing array
foreach ($upcomingDates as $key => $value) {
    // Check if the value is already in the container array
    // If this is the case, its a duplicate.
    if (array_key_exists($value['start_date'], $container)) {
        $container[$value['start_date']]++;
        echo $value.' is a duplicate with key '.$key;
    }

    // Add each value to the array
    $container[$value['start_date']] = 1;
}

Another method is to use array_count_values()

foreach(array_count_values($upcomingDates) as $value => $c) {
    if ($c > 1) {
        echo $value.' is a duplicate';
    }
}

Note that the second option won't work if your $upcomingDates is an array of arrays.

edited Jun 14 '16 at 14:28

answered Jun 14 '16 at 14:12

Peter

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Thanks for your answer. In your second method, I obtain this error : `Can only count STRING and INTEGER values` – Ty Yt Jun 14 '16 at 14:22
Are your values `DateTime` objects? – Peter Jun 14 '16 at 14:23
They're stored in varchar – Ty Yt Jun 14 '16 at 14:25
@TyYt I edited my answer to let the first part work for you. – Peter Jun 14 '16 at 14:31

score 0 · Answer 2 · answered Jun 14 '16 at 13:52

You can make an empty array before the for loop, and add each value in as a key. Then, on each iteration you can check that array for the key, like so:

$values = [];
foreach ($upcomingDates as $value) { //$upcoming is the array with my sql request
    if(isset($values[$value])) //duplicate value found
        //do something here
    $values[$value] = 1;
}

score 0 · Answer 3 · answered Jun 14 '16 at 13:55

0

Since you're ordering your events by start_date:

for ($i = 0, $length = count($upcomingDates); $i < $length; $i++) {
    $date = $upcomingDates[$i];

    if (isset($upcomingDates[$i + 1]) &&
        $upcomingDates[$i + 1]['start_date'] == $date['state_date']) {
        echo 'this and the next date are equal';
    }
}

answered Jun 14 '16 at 13:55

deceze

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Thanks for your answer, let me understand it and try :) – Ty Yt Jun 14 '16 at 14:23

score 0 · Answer 4 · answered Jun 14 '16 at 14:02

0

Try out GROUP BY

look here: GROUP BY

answered Jun 14 '16 at 14:02

jrergon

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1

Why should the OP "try this"? A good answer will always have an explanation of what was done and why it was done in such a manner, not only for the OP but for future visitors to SO. Futhermore: links will get deleted one day, then your posting wouldnt have any impact anymore. – B001ᛦ Jun 14 '16 at 14:09

score 0 · Answer 5 · edited May 23 '17 at 11:52

0

if you want to find duplicates, then you can directly get it from database ex.
SELECT * FROM EVENTSDATE where event='$id' and start_date>='$today' GROUP BY start_date having count(start_date) > 1 order by start_date asc
or you can find duplicates from resulting array return only duplicated entries from an array

edited May 23 '17 at 11:52

Community

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answered Jun 14 '16 at 14:06

Sanjay

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Yes, already done in my SQL request but I would like to try in PHP. A little challenge ^^ Thanks ! – Ty Yt Jun 14 '16 at 14:21

Check if multiple dates are the same in foreach

5 Answers5