This is an old revision of the document!
The $COMPARE_DATES function determines the interval between two dates and returns that value as a fractional floating point value. The interval will default to days unless overridden using the unit parameter.
$COMPARE_DATES ( <date_column1 | 'date_string1' > , < date_column2 | 'date_string2 >
[, [date_unit]
[, options]
)
An expression resulting in a date-class or string-class datatype
An expression resulting in a date-class or string-class datatype
A string containing a unit abbreviation identifying the type of interval. The supported abbreviations are the same as those found in the EXTRACT function.
Valid date_unit options:
| Date_unit | Description |
|---|---|
| YEAR | Year |
| MONTH | Month |
| DAY | Day |
| HOUR | Hour |
| MINUTE | Minute |
| SECOND | Second |
| A | Lowercase am/pm indicator |
| AA | Uppercase AM/PM indicator |
| D | Non-zero-filled day-of-month (1, 2, 3) |
| 0D | Zero-filled day-of-month (01, 02, 03) |
| DD | Day of year (44) |
| 0DD | Zero-filled day of year (044) |
| F | Non-zero-filled fraction of a second (1, 2) |
| 0F | Zero-filled fraction of a second (01, 02) |
| H | 12-hour, non-zero-filled hour of day (12, 1) |
| 0H | 12-hour, zero-filled hour of day (12, 01) |
| HH | 24-hour, non-zero-filled hour of day (24, 1) |
| 0HH | 24-hour, zero-filled hour of day (24, 01) |
| J | Non-zero-filled Julian date (1, 2) |
| 0J | Zero-filled Julian date (01, 02) |
| M | Non-zero-filled month number (1-January, 2-February) |
| 0M | Zero-filled day-of-month number (01-January, 02-February) |
| MM | Three-character month abbreviation (Jan, Feb) |
| MMM | Fully spelled month (January, February) |
| N | Non-zero-filled minute of hour (1, 2) |
| 0N | Zero-filled minute of hour (01, 02) |
| Q | Quarter of the year (1) |
| Quarter of the year abbreviation (Q1) | |
| QQQ | Quarter of the year name (First Quarter) |
| S | Non-zero-filled second of minute (1, 2) |
| 0S | Zero-filled second of minute (01, 02) |
| W | Day of the week number (1-Sunday, 2-Monday) |
| WW | Three-character day-of-week abbreviation (Sun, Mon) |
| WWW | Fully spelled day-of-week (Sunday, Monday) |
| YY | Two-digit year (99, 00) |
| YYYY | Four-digit year (1999, 2000) |
A string containing options for this functions. No options exist at this time.
The result of the $COMPARE_DATES function is an INTEGER datatype reflecting the number of units between the two dates.
> select $compare_date('20090101', current_date, 'DD') from $omnidex
$COMPARE_DA
-----------
462