mmyear

mmyear is a term used in data organization to refer to a time key that encodes a specific month and year. The standard form is MMYYYY, a six-character combination that places the two-digit month before the four-digit year. In many contexts, mmyear is stored as a numeric value, but preserving leading zeros is important; otherwise the month portion can be misinterpreted.

Use and notation

mmyear functions as a compact index for monthly aggregates, such as sales, weather, or other time-series data where day-level detail is unnecessary. Because MMYYYY is ordered lexicographically in the same way as time, it supports straightforward chronological sorting when stored as a string, and also as a numeric key with appropriate handling of leading zeros.

Conversions

To create mmyear from a date, format the date as a two-digit month followed by a four-digit year and concatenate. To revert, take the first two digits as the month and the remaining four as the year. If mmyear is stored as an integer, be aware that leading zeros may be lost; in such cases, division and modulo operations with 10000 can be used to extract year and month, but the result should be formatted with two digits for the month.

Applications and limitations

mmyear is useful for compact, month-based indexing and reporting. It does not encode day information and is not a full date data type, which can limit date arithmetic and alignments across different calendar systems. Its effectiveness depends on consistent formatting and clear documentation within datasets.

See also

YYYYMM, date encoding, time-series indexing.