Question in SQL...

 This question I found in one of the exam papers.

     transaction(transno, acctno, date, amount)

  The amount attribute value is positive for deposits and negative for withdrawals.

(a) Define an SQL view TP containing the information (acctno,
T1.date, T2.amount) for every pair of transactions T1, T2 such that T1 an T2 are transactions on same account and the date of T2 is <= date of T1.

(b) Using only the above view TP, write a query to find for each
account the minimum balance it ever reached (not including the balance when the account is created). Assume there is atmost one transaction per day on each account, and each account has had atleast one transaction since it was created.
  To simplify your query, break it up into 2 steps by defining an intermediate view V.

  For the (a) part I feel the query to be as follows: