问题
As the title states, I don't understand why the sp_executeSQL would generate a completely different execution plan than running the query from Sql Management Studio.
My query in question will take 3 seconds when run from SQL management Studio, where as the query run in management studio via sp_executeSQL will take 5 minutes.
I've updated statistics, and reviewed indexes, but the fact remained in my head that the execution plan from sp_executeSQL was FAR worse than running the sql directly from my management studio.
So here is my question: Why would the execution plans differ SO much between running the query in these two different ways?
Thanks
回答1:
see this
basically, there can be multiple [execution] plans for the same procedure
回答2:
Consider this. When you execute a stored procedure, this procedure will have its own execution plan. When you execute a query statement, again it will have its own execution plan. Now when using sp_executeSQL you are running this stored procedure to execute a query dynamically. So in essence its execution plan is the combination of sp_executeSQL and your query.
来源:https://stackoverflow.com/questions/5487891/why-would-the-exact-same-sql-query-result-with-a-different-execution-plan-when-e