tricky update query

Everyone,

Help needed on building a query with the following condition:

certain rows, which satisfy a condition in a where clause, needs to have their attribute values updated by those present in the previous row.

Consider, for example, a table with 4 columns flowid flowTime flowVal flowtype

001      02/10/01 8:00am       15                A
001      02/10/01 9:00am       12                F
001      02/10/01 10:00am      17                A
001      02/10/01 11:00am      23                F
001      02/10/01 12:00pm      10                F

Here flowId and FlowTime is the key.
 We have an entry in the table for every hour, for all flowId's. So the problem is I need to UPDATE the flowValue, whose FlowType is "F" with the FlowVal of the row immediately above this row, whose flow type is not "F"

For example, the FlowVal of row# 2 should be "15", because the flowType of this row is "F" and the row immediately above it has flow type not equal to "F"

Similarly rows 4 & 5, should have a flow value of "17"

How can this be done in a single query? The values are already sorted in the table and the entry is for every hour on the hour.

Any help is appreciated. Please post the reply to newsgroup only.

Thanks in advance. Received on Thu Feb 15 2001 - 20:53:43 CST