Modifies a column's values in existing rows of a table or view. Restriction: You cannot use UPDATE on a table accessed via an engine that does not support UPDATE processing. You can update one or more ...

9 best practices for faster SQL queries Retrieve only the columns you need Use CASE instead of UPDATE for conditional column updates Keep large-table queries to a minimum Pre-stage your data ...

If you only want to update values in table A when there are matching records in table B, then an inner join is the way to go. If you have calculations that need to vary based on optional data, the ...