Single Column Single Row and TABLE SCAN – SQL in Sixty Seconds #111


 

Can a single column and single row result do an entire table scan? I recently got this question in my  Comprehensive Database Performance Health Check. I think it is a fair question when we retrieve very few rows from a gigantic table, we do expect that we will read only a few rows and not a complete table.

However, the reality is very interesting. I have built this video where I am reading a single column and single row from a table and it is reading the entire table and also does a table scan. Remember table scan is not necessary