Table: top_1999_singles
Columns: volume_issue
issue_date_s
weeks_on_top
song
artist

Question: What date did the song by jennifer lopez get issued?
SQL: SELECT "issue_date_s" FROM top_1999_singles WHERE "artist" = 'jennifer lopez'

Question: What song came from volume:issue 68:20-24?
SQL: SELECT "song" FROM top_1999_singles WHERE "volume_issue" = '68:20-24'