In SQL Server, if you’re getting error Msg 4127 that reads “At least one of the arguments to COALESCE must be an expression that is not the NULL constant”, it’s probably because all of your arguments to the COALESCE() expression are the NULL constant.
To fix this issue, make sure at least one argument is not the NULL constant.
In SQL Server, the COALESCE() expression returns its first non-null argument.
The way it works is, we pass a list of arguments to the expression, it evaluates the arguments in order and returns the current value of the first expression that initially doesn’t evaluate to NULL.
In SQL Server, we can use the following method to return a date and time based on a given Unix timestamp.
The Unix timestamp (also known as Unix Epoch time, Unix time, or POSIX time) is the number of seconds that have elapsed since 00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC).
Continue readingBelow are three options for using T-SQL to return the first day of the month in SQL Server.
This could be the first day of the current month, or the first day of a month based on a given date.
Continue readingIf you’re getting error message “Msg 206” that reads “Operand type clash: date is incompatible with int” in SQL Server while trying to add to (or subtract from) a date, it’s probably because you’re trying to perform arithmetic between an integer and a date value.
To fix this issue, either change the date value to a datetime value or use the DATEADD() function.
If you have a column in a SQL Server database table that contains character data, but some rows also contain numbers within that data, you can use the following technique to return just those rows that don’t contain numbers.
Numbers can be represented by words and other symbols, but for the purpose of this article, “number” means “numerical digit”. So we’re finding values that don’t contain any numerical digits.
Continue readingThe following examples use T-SQL to delete duplicate rows in SQL Server while ignoring the primary key or unique identifier column.
More specifically, the examples delete duplicate rows but keep one. So, given two identical rows, one is deleted and the other remains. This is often referred to as “de-duping” the table, “deduplication” of the table, etc.
Continue readingBelow are five options for returning rows that contain uppercase letters in SQL Server.
Continue readingIn SQL Server, we can use the ISNUMERIC() function to return numeric values from a column.
We can alternatively run a separate query to return all values that contain numeric data.
Continue readingHere are examples of returning rows that contain non-alphanumeric characters in SQL Server.
Non-alphanumeric characters include punctuation characters like !@#&()–[{}]:;',?/* and symbols like `~$^+=<>“, as well as whitespace characters like the space or tab characters.