I use MySql on a semi-regular basis to analyse data to determine trends and basic statistical information (e.g. min / max / avg) however, one of the issues is often I only care about the information when it occurs within business hours (which in my case is defined as Monday - Friday between 9am and 5pm.Whilst I was aware of WHERE x = y fields, e.g. where sensor = a which lets you only show values in the table where the field sensor = a, I must admit I was not aware of the weekday, hour and between operators.As a result i thought it would