Implied Extract of Day, Month and Year Teradata

Compatibility: Teradata Extension

Although the EXTRACT works great and it is ANSI compliant, it is a function. Therefore, it must be executed and the parameters passed to it to identify the desired portion as data. Then, it must pass back the answer. As a result, there is additional overhead processing required to use it.

It was mentioned earlier that Teradata stores a date as an integer and therefore allows math operations to be performed on a date. The syntax for implied extract:

The following SELECT uses math to extract the three portions of Mike's literal birthday:

1 Row ReturnedSELECT uses math to extract the three portions

Remember that the date is stored as yyymmdd. The literal values are used here to provide a date of Oct. 1, 2001. The day portion is obtained here by making the dd portion (last 2 digits) the remainder from the MOD 100. The month portion is obtained by dividing by 100 to eliminate the dd to leave the mm (new last 2 digits) portion the remainder of the MOD 100. The year portion is the trickiest. Since it is stored as yyy (yyyy – 1900), we must add 1900 to the stored value to convert it back to the yyyy format. What do you suppose the EXTRACT function does? Same thing.

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