Query to split the comma seperated column value into the multiple rows - mysql

Question

i have one mysql table name called mem_exam_dates.
+---------+-------------+----------------------------------+
| rec_id | mem_name | exam_dates |
+---------+-------------+----------------------------------+
| 1 | Raju | 2015-01-05,2015-05-09,2018-05-09 |
| 2 | Rajes | 2015-10-05,2015-12-09,2018-09-09 |
+---------+-------------+----------------------------------+
now i want to display the result as below.
+-------+---------------+
| Raju | Exam Dates |
+-------+---------------+
| 2015-01-05 |
| 2015-05-09 |
| 2018-05-09 |
+-----------------------+
i am writing the query like
select * from mem_exam_dates where rec_id=1
from the above query i am getting total exam dates as single string.
but i want the exam dates as below.
+----------------+
| 2015-01-05 |
| 2015-05-09 |
| 2018-05-09 |
+----------------+
what is the query for that one?
if anybody knows let me know...
Thanks in advance
kalyan

Answer 1

In MySQL you can extract a part from string with SUBSTRING_INDEX.
So you can try the follow SQL
SELECT SUBSTRING_INDEX(exam_dates, ',', 1) as first
, SUBSTRING_INDEX(SUBSTRING_INDEX(exam_dates, ',', 1), ',', -1) as second
, SUBSTRING_INDEX(exam_dates, ',', -1) as third
In .NET you can use split()
https://msdn.microsoft.com/de-de/library/b873y76a%28v=VS.110%29.aspx
If you have the column in a variable named exam_dates you can use:
string [] dates = exam_dates.Split(new Char [] {','});
So you have an array of all dates.

Answer 2

You need to process the data in the server side language. If you are using PHP, you would use explode.
For example:
$dates= explode(",", $longdatestring);
echo $dates[0]; // date1
echo $dates[1]; // date2
To find the number of dates returned, simply count the elements in your array.
$numberofdates = count($dates);
Or look through the array untill you run out of elements.
foreach ($dates as $date) {
echo $date;
}
For further details in PHP:
https://secure.php.net/manual/en/function.explode.php