In Access, the DateDiff function returns the number of time intervals between two dates.
The syntax for the DateDiff function is:
DateDiff ( interval, date1, date2[, firstdayofweek[, firstweekofyear]] )
You can use the DateDiff function to determine how many time intervals exist between two dates. For example, you can use DateDiff to calculate the number of days between an order date and its shipdate or the number of weeks between today and the end of the year.
interval is the interval of time to use to calculate the difference between date1 and date2. The following is a list of valid interval values.
| Interval | Description |
| yyyy | Year |
| q | Quarter |
| m | Month |
| y | Day of year |
| w | Weekday |
| ww | Week |
| h | Hour |
| n | Minute |
| s | Second |
date1, date 2 are the two dates to calculate you want to use in the calculation.
firstdayofweek is optional argument that specifies the first day of the week. If not specified, Sunday is assumed. If not specified, the first week is assumed to be the week in which Jan 1 occurs. The following is a list of valid parameters for firstweekofyear.
| Constant | Value | Description |
| vbUseSystem | 0 | Use the NLS API settings |
| vbSunday | 1 | Sunday (default used) |
| vbMonday | 2 | Monday |
| vbTuesday | 3 | Tuesday |
| vbWednesday | 4 | Wednesday |
| vbThursday | 5 | Thursday |
| vbFriday | 6 | Friday |
| vbSaturday | 7 | Saturday |
firstweekofyear is optional argument that specifies the first week of the year. The following is a list of valid parameters for firstweekday.
| Constant | Value | Description |
| vbUseSystem | 0 | Use the NLS API settings |
| vbFirstJan1 | 1 | Start with the first week in which January 1 occurs (default). |
| vbFirstFourDays | 2 | Start with the first week in the year that has at least 4 days |
| vbFirstFullWeek | 3 | Start with the first full week of the year |
Examples
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VBA Code
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This example uses the DateDiff function to display the number of days between a given date and today. Now the MyNumber variable would contain the value of 64.
SQL query
You can also use the DateDiff function in a query.
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