% This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.

**Examples**

```esql
ROW date1 = TO_DATETIME("2023-12-02T11:00:00.000Z"), date2 = TO_DATETIME("2023-12-02T11:00:00.001Z")
| EVAL dd_ms = DATE_DIFF("microseconds", date1, date2)
```

| date1:date | date2:date | dd_ms:integer |
| --- | --- | --- |
| 2023-12-02T11:00:00.000Z | 2023-12-02T11:00:00.001Z | 1000 |

When subtracting in calendar units - like year, month a.s.o. - only the fully elapsed units are counted.
To avoid this and obtain also remainders, simply switch to the next smaller unit and do the date math accordingly.

```esql
ROW end_23=TO_DATETIME("2023-12-31T23:59:59.999Z"),
  start_24=TO_DATETIME("2024-01-01T00:00:00.000Z"),
    end_24=TO_DATETIME("2024-12-31T23:59:59.999")
| EVAL end23_to_start24=DATE_DIFF("year", end_23, start_24)
| EVAL end23_to_end24=DATE_DIFF("year", end_23, end_24)
| EVAL start_to_end_24=DATE_DIFF("year", start_24, end_24)
```

| end_23:date | start_24:date | end_24:date | end23_to_start24:integer | end23_to_end24:integer | start_to_end_24:integer |
| --- | --- | --- | --- | --- | --- |
| 2023-12-31T23:59:59.999Z | 2024-01-01T00:00:00.000Z | 2024-12-31T23:59:59.999Z | 0 | 1 | 0 |