I actually got this from a piano and just played the notes on the bass. But also i didnt 
any happy birth day tabs so i made my own... Hope you guys like it.

g|------------------------|  C D F E
d|---------3--------------|
a|-3-3-5-3---7------------|
e|------------------------|

g|------------------------|  C D G F
d|---------5-3------------|
a|-3-3-5-3----------------|
e|------------------------|

g|------5-2---------------|  C C A F E D
d|----------3-------------|
a|-3-3--------7-5---------|
e|------------------------|

g|-3-3-2------------------|  A# A F G F
d|-------3-5-3------------|
a|------------------------|
e|------------------------|