>I've run into this issue. It basically comes down to the plan that is being used inside the function is not the same as the plan used when you issue the query manually >outside of the function. Although I'm no expert on when plans are prepared and re-evaluated for functions, I know that they are not re-evaluated each time to execute the >function.
in my case; both direct query and sql function gererate same execution plan. Also, execution plan belongs to the sql function better than direct sql query plan. But, direct sql result comes less than 1 second. sql function result comes about in 50 seconds.