PHP: analyse variable -

i creating website school.

i have subjects of student saved in database.

it's saved --> 1,2,3,6,7

this means student x subject id 1,2,3, 6 , 7

the subjects 1 student returned database in 1 variable $subjects output subject name (subject names stored in database). since variable returned in $subjects not 1 subject, multiple, can't search subject name. possible convert $subjects array $subjects[0] 1 in example , $subjects[1] 2 (see above @ it's saved this).

simply said: should not $subjects = 1,2,3,6,7 but

$subjects[0] = 1 $subjects[1] = 2 $subjects[2] = 3 $subjects[3] = 6 $subjects[4] = 7 

you can use explode convert string array:

explode(',', $students); 

it should noted, however, exploding , doing more queries database subject names inefficient way this. rather store students subjects in 1 field should create whole table relationship. in additional students table , subjects table, have relationship:

table: studentsubjects

student | subject -----------------    1    |   1    1    |   2    1    |   3    1    |   6    1    |   7    2    |   2    2    |   4    2    |   6    2    |   8    3    |   3 

then can query database , list of subject names particular student, or group of students, in 1 query.