Sams Teach Yourself SQL in 24 Hours, Third Edition By Ronald R. Plew, Ryan K. Stephens
Table of Contents
Hour 12. Understanding Dates and Times
Q&A
Q1:
Why do implementations choose to deviate from a single standard set of data types and functions?
A1:
Implementations differ as far as the representation of data types and functions mainly because of the way each vendor has chosen to internally store data and provide the most efficient means of data retrieval. However, all implementations should provide the same means for the storage of date and time values based on the required elements prescribed by ANSI, such as the year, month, day, hour, minute, second, and so on.
Q2:
What if I want to store date and time information differently than what is available in my implementation?
A2:
Dates can be stored in nearly any type of format if you choose to define the column for a date as a variable length character. The main thing to remember is that when comparing date values to one another, it is usually required to first convert the character string representation of the date to a valid DATETIME format for your implementation; that is, if appropriate conversion functions are available.
