I heard my PM saying today "Their are two types of Idiots. One who will take multiple trips to the database to compare value. Others who will take the values in memory and compare then their". We have a situation. We need to take values from one table and check if it exists in the second table. Depending on weather it exists in the second table or not, we need to display with / without highlight it in the datagrid. There is one catch. The query is written by the user in one of the application screen and the user has no idea that the 2nd condition table needs to be applied. I know you would debate that we need to create a screen, so that the user will select what is required instead of writing the query. I know... but we need this asap. Screen will be in the next release. Let me elaborate: Consider that we have table A and table B. Both these tables have ID column. The user writes (on the application screen) SELECT * FROM A I can check that this ID does not exist in