options value is 10,15,20,15,25,10

options value should be 10,15,20,25

$duplicateValues = explode(',',$sqlResult);
$duplicateValues= array_unique($duplicateValues);

SUBSTRING_INDEX(str, delim, count)

INSTR (ori_str, sub_str)

POSITION(substr IN str)

select * from Order join numbers on char_length(options) - char_length(replace(options, ',', '')) >= n - 1