The Following query has brought records for John’s math record from student’s score table named MyTable

Query1

ID ---- Studentname ------ subject ---- score ---- month

.

12 ----John ---- ---- ---- math ---- ---- 17 ---- ---- January

18 ---- John ---- ---- ---- math ---- ---- 12 ---- ---- February

54 ---- John ---- ---- ---- math ---- ---- 19 ---- ---- April

71 ---- John ---- ---- ----math ---- ---- 7 ---- -- ---- Jun

92 ---- John ---- ---- ---- math ---- ----15 ------ ---- Sep

How can we get the score from previous exam?

Query2

ID ---- Studentname ---- subject ---- score ------ month ----previous_Score

.

12 ---- ----John ---- ---- --- math ---- 17 ---- ---- January ---- ---- 17 (or null)

18 ---- ---- John ---- ------- math ---- 12 -- ------ February --- ----- 17

54 ---- ---- John ---- --- ---- math ---- 19 -- ------ April ---- ------- 12

71 ---- ---- John ---- --- ---- math ---- 7 ---- ---- Jun ---- ---------- 19

92 ---- ---- John ---- --- ----math ---- 15 ---- ---- Sep ---- ---- ------ 7

I put the dashes just to better picture the fields.

Thank you