How to find unique values within a string array that contains semi-colon delimited values?

I'm using PHP and MySQL to power a small application. I'm importing data from an .ods file. The import produces ugly string values delimited by semi-colons. There are less than 1000 rows of data within the resulting table.

Example:

"SELECT DISTINCT submissions.tags FROM submissions";

#quality;#RIE;#PDSA;#6S;#MyEvent;
#quality;#RIE;#PDSA;#teamengagement;#6S;

I'm looking to extract the unique values beginning with the # character. An example of the resulting unique array would look like:

#quality;#RIE;#PDSA;#6S;#MyEvent;#teamengagement;

I'm wondering if this can be accomplished using strictly SQL or, if this would best be accomplished using PHP?

In either instance, I'm not knowledgeable of how to go about accomplishing this task?

Any guidance would be appreciated. Cheers!