Database Systems Practice Test

Getting the leftmost portion of a string means taking the first n characters from the start. The Left function does exactly this: Left(string, n) returns the first n characters. For example, Left('abcdef', 3) yields 'abc'. The other options are not as direct: Right grabs characters from the end, Mid requires a starting position (and length) to extract a middle portion, and Substring is a general form that can return any portion by specifying a start index and length (you could use Substring(string, 1, n) to mimic the left part, but that’s more verbose). So the best fit for leftmost characters is the Left function.