Question

I have a problem with processing a SQL Server database dump in PHP.

I have one column called datatime with values like :

0x0000a0af00d7f2eb

I need to extract, in PHP, the date and time values of this column. I don’t have SQL Server available so I can’t use the obvious solution of CAST(0x0000a0af00d7f2eb AS datetime).

Someone has told me that this hex: 0000a0af00d7f2eb is created by 4 bytes of date and 4 bytes of time.

So I know that:

When I will change 0000a0af (first 4 bytes) to decimal I will get number of days from 1900. That works fine.

But when I’m trying to change last the 4 bytes (so there should be time) : 00d7f2eb to decimal I’m getting something which I can’t understand. It should be a time from midnight in milliseconds and sometimes this value is ~3 times lower.

Could anyone help in converting 0000a0af00d7f2eb to date? I know that time is between 5 AM and 11 PM, and the day is in last week.

Answer 1

According to the linked article in the other question linked to by Rene, SQL Server stores 3.33 millisecond intervals in the second set of 4 bytes, not milliseconds. So if you’re calculating with milliseconds, you will indeed be getting a time about 1/3 of what it should be. Using your example, let’s start by converting to decimal

00d7f2eb -> 14152427 3.3ms intervals

Now multiply out by 3.3 to convert to milliseconds, and divide by 1000 to get seconds

14152427 * 3.3 / 1000 ~ 47127.58

So this represents about 47 thousand seconds after midnight. Dividing by 3600 seconds in an hour

47127.58 / 3600 ~ 13.091

So this represents a time of about 13.1 hours after midnight, which agrees with the result of the cast done in SQL Server.