mssql

DATEDIFF() vs DATEDIFF_BIG() in SQL Server: What’s the Difference?

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If you’ve ever needed to find the difference between two dates in SQL Server, you might have used the DATEDIFF() function. This function returns the amount of time between two dates using a datepart specified by you. For example, you could use it to return the number of days between date 1 and date 2. You can also get it to return the number of minutes, seconds, months, years, etc.

The DATEDIFF_BIG() function works exactly the same way, but with one subtle difference: Its return data type.

So the difference between these two functions is the data type of their return value.

  • DATEDIFF() returns a signed integer (int)
  • DATEDIFF_BIG() returns a signed big integer (bigint)

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How to Return the Unix Timestamp in SQL Server (T-SQL)

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You might have noticed that SQL Server doesn’t have an equivalent of MySQL‘s UNIX_TIMESTAMP() function.

However, it’s not that difficult to return the Unix timestamp in SQL Server.

The Unix timestamp (also known as Unix Epoch time, Unix time, or POSIX time) is simply the number of seconds that have elapsed since 00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC). Therefore, in SQL Server we can use a couple of T-SQL functions to return this.

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Examples of Converting ‘time’ to ‘datetime’ in SQL Server (T-SQL)

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This article contains examples of converting a time value to a datetime value in SQL Server.

When you convert a time value to datetime, extra information is added to the value. This is because the datetime data type contains both date and time information. The time data type, on the other hand, only contains time information. Therefore, date information is added to the value when you perform such a conversion. Specifically, the date is set to ‘1900-01-01’.

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Examples of Converting ‘date’ to ‘datetimeoffset’ in SQL Server (T-SQL)

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This article contains examples of converting a date value to a datetimeoffset value in SQL Server.

When you convert a date value to datetimeoffset, extra information is added to the value. This is because the datetimeoffset data type contains both date and time information, as well as the time offset information. In other words, the datetimeoffset data type defines a date that is combined with a time of a day that has time zone awareness and is based on a 24-hour clock. The date data type, on the other hand, only contains date information.

When we convert from date to datetimeoffset, the time (and time zone offset) is automatically added to the value. However, you can always change the value if required (including the time zone offset).

The datetimeoffset data type also allows you to specify the fractional seconds precision. If you don’t specify this, it uses a scale of 7. This means it will include 7 digits on the right side of the decimal point.

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Examples of Converting ‘date’ to ‘smalldatetime’ in SQL Server (T-SQL)

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This article contains examples of converting a date value to a smalldatetime value in SQL Server.

When you convert a date value to smalldatetime, extra information is added to the value. This is because the smalldatetime data type contains both date and time information. The date data type, on the other hand, only contains date information.

However, there are cases where a date to smalldatetime conversion might fail. In particular, if the date value is outside the range supported by smalldatetime then it will fail with an error.

In any case, below are examples of converting between these two data types.

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Examples of Converting ‘date’ to ‘datetime2’ in SQL Server (T-SQL)

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This article contains examples of converting a date value to a datetime2 value in SQL Server.

When you convert a date value to datetime2, extra information is added to the value. This is because the datetime2 data type contains both date and time information. The date data type, on the other hand, only contains date information.

The datetime2 data type is basically an extension of the datetime data type. It has a larger date range, a larger default fractional precision, and optional user-specified precision.

In any case, the conversion process is exactly the same regardless of the data type. The only difference is the amount of information that’s available between date, datetime and datetime2.

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Examples of Converting ‘date’ to ‘datetime’ in SQL Server (T-SQL)

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This article contains examples of converting a date value to a datetime value in SQL Server.

When you convert a date value to datetime, extra information is added to the value. This is because the datetime data type contains both date and time information. The date data type, on the other hand, only contains date information.

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How to Display a Date in German Format in SQL Server (T-SQL)

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When formatting a date using the FORMAT() function in SQL Server, the date will be formatted according to the language of your local session. However, you can override this by specifying a culture to use, or using a custom date format.

This article demonstrates how to explicitly specify a German date format by using the optional “culture” argument of the FORMAT() function. It also demonstrates how to use your own custom date format if that is more desirable.

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How to Display a Date in British Format in SQL Server (T-SQL)

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This article demonstrates how to explicitly format a date in Great Britain English format when using the T-SQL FORMAT() function in SQL Server.

You may or may not need to use this argument, depending on the language of your local session. However, here’s how to explicitly specify Great Britain English date format.

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