MySQL has a bunch of functions that enable us to get values from another row in the same column. This makes it easy for us to do stuff like calculate the difference between a value in the current row and one in another row, even if it’s in the same column.
Here are five options for calculating the difference between a value in the current row and a value in a different row but in the same column.
Continue readingThe release of SQL Server 2022 came with the introduction of the DATE_BUCKET() function.
The DATE_BUCKET() function allows us to arrange data into groups that represent fixed intervals of time. It returns the date/time value that corresponds to the start of each date/time bucket, as defined by the arguments passed to the function.
If you’re getting SQL Server error number 189 that reads “The greatest function requires 1 to 254 arguments“, it’s probably because you’re either passing too few or too many arguments.
As the error message alludes to, you need to pass at least 1 argument, and no more than 254 arguments when using the GREATEST() function.
To fix this issue, be sure to pass at least 1 argument, and no more than 254 arguments.
Continue readingIn SQL NULL is a special value, or mark, that is used to indicate the absence of any data value. And this is the case with SQL Server.
But SQL Server also has a special use of NULL in certain cases.
In SQL Server, we can use the DATETRUNC() function to truncate a date/time value to a specified precision.
For example, we could use it to truncate a date value like 2024-10-25 to 2024-01-01, or a time value like 10:35:12 to 10:00:00.
The DATETRUNC() function was introduced in SQL Server 2022Â (16.x).
If you’re getting an error message that reads “The function ‘LAST_VALUE’ must have an OVER clause with ORDER BY.” when using the LAST_VALUE() function in SQL Server, it’s probably because you’ve omitted the ORDER BY clause from the OVER clause.
The LAST_VALUE() function requires an OVER clause that contains an ORDER BY clause. This error happens when we include the OVER clause but not the ORDER BY clause.
To fix this error, add an ORDER BY clause to the OVER clause.
Sometimes when we run a SQL query, we only want to see unique rows. But depending on the columns we’re selecting, we might end up with duplicate rows. And this could happen without even knowing it, especially with large data sets.
But it doesn’t have to be this way.
Fortunately most SQL databases provide us with an easy way to remove duplicates.
Continue readingIn SQL Server, we can use the TRIM() function to remove leading and trailing characters from a given string.
A common use case is to remove whitespace from the start and end of the string, but we can also specify other characters to remove.
Also, as from SQL Server 2022, we can specify which side of the string to remove the characters from (i.e. leading, trailing, or both).
Continue readingIn SQL Server, we can use the T-SQLÂ RTRIM() function to remove trailing blanks from a given string. Trailing blanks are white spaces, tabs, etc that come at the end of the string.
Also, as from SQL Server 2022, we can specify other trailing characters to remove from the string.
Continue readingIn SQL Server, we can use the T-SQL LTRIM() function to remove leading blanks from a given string.
Also, as from SQL Server 2022, we can specify other leading characters to remove from the string.
Continue reading