The optimizer is the part of SQL Server that takes your query and reorders and rearranges your query to find the optimal execution plan. In theory.   In practice, that doesn’t always work out well. Often, the optimizer manages to come up with brilliant ways to execute a complex query very efficiently – but sometimes, it misses an ...

I guess that many people using UPDATE … FROM on a daily basis do so without being aware that they are violating all SQL standards.   All versions of the ANSI SQL standard that I checked agree that an UPDATE statement has three clauses – the UPDATE clause, naming the table to be updated; the SET clause, specifying the columns to change and ...