The traditional advice for improving performance for multiple UPDATE statements is to “prepare” the required query once, and then “execute” the prepared query once for each row requiring an update.
But in many cases this only provides a modest improvement as each UPDATE operation still requires a round-trip communication with the database server.
There can be multiple trips for each car with each trip having a start and stop time.
Top Speed desc, Time Sent desc ) as CD The #summary temporary table is creating summarised data about trips undertaken by a car.
A more effective solution to this problem is to attempt to reduce the number of UPDATE statements.
For small numbers of rows requiring updates, it can be adequate to use an UPDATE statement for each row that requires an update.
But if there are a large number of rows that require an update, then the overhead of issuing large numbers of UPDATE statements can result in the operation as a whole taking a long time to complete.
Driver from ( select top 1 Top Speed, Time Sent, Driver from Car Data where Car Data.
The Car Data table contains all the detailed car data like speed and position etc.
Driver from ( select Vehicle Id, Time Sent, Driver, Max(Top Speed), Max(Time Sent) from Car Data GROUP BY Vehicle Id, Time Sent, Driver ) as CD where CD. A requirement arises in many systems to update multiple SQL database rows.