SQL Server has a CHOOSE() function that returns a list item at a given position. MySQL also has an equivalent function, but with a different name.
In MySQL, the ELT() function does essentially the same thing that CHOOSE() does in SQL Server. It allows you to find the list item at a given position within the list.
Starting from SQL Server 2012, you can use the T-SQL CHOOSE() function to find a list item at a specified index position within a list.
The syntax goes like this:
CHOOSE ( index, val_1, val_2 [, val_n ] )
Where index is an integer that represents the position within the list that you want to return.
Here’s an example:
SELECT CHOOSE(3, 'Marge', 'Homer', 'Bart') AS 'Who is at 3?';
Result:
Who is at 3? ------------ Bart
In this case, we want to find the item at position 3. The item at position 3 is Bart.
Starting from SQL Server 2012, you can format numeric types using the T-SQL FORMAT() function. This function accepts three arguments; the number, the format, and an optional “culture” argument.
It returns a formatted string of type nvarchar.
The format is supplied as a format string. A format string defines how the output should be formatted.
Here’s an example:
SELECT FORMAT(1, 'N');
Result:
1.00
In this case, I used N as the second argument. This is the standard numeric format specifier for Number. This particular format specifier (N) results in the output being formatted with integral and decimal digits, group separators, and a decimal separator with optional negative sign. This argument is case-insensitive, so either N or n is fine.
In SQL Server, you can use the T-SQL FORMAT() function to format the date and/or time. Simply provide two arguments; the date/time and the format to use.
The format is supplied as a format string. A format string defines how the output should be formatted.
The FORMAT() function also accepts an optional “culture” argument, which allows you to specify a language/locale that the results should adhere to.
In SQL Server and Azure, if you need to concatenate two or more strings, you can use the T-SQL CONCAT() function. As with any basic concatenation operation, this function joins the strings together, end-to-end.
But what if you need to add a separator between each string?
For example, you might want to make a comma-separated list of strings. In this case, you’d want to insert a comma in between each string. Like this:
Paris, France
Instead of this:
ParisFrance
Fortunately, T-SQL provides the CONCAT_WS() function that helps you do exactly that. The CONCAT_WS() function works just like the CONCAT() function, except that it takes an extra argument – the separator you’d like to use.
In SQL Server, you can concatenate two or more strings by using the T-SQL CONCAT() function. You can also use SQL Server’s string concatenation operator (+) to do the same thing. Both are explained here.
In SQL Server (and in any computer programming environment), string concatenation is the operation of joining character strings end-to-end.
Here’s an example:
SELECT CONCAT('Peter', ' ', 'Griffin') AS 'Full Name';
Result:
Full Name ------------- Peter Griffin
Note that I actually concatenated 3 strings here. I concatenated the first name, the last name, plus a space.
In SQL Server, you can use the LEN() function to return the number of characters in a string. This is a Transact-SQL function that can also be used in Azure databases.
In MySQL, you need to use the CHAR_LENGTH() function.
If you’ve been working with SQL Server for any length of time, you might have encountered the Datalength() function. This function returns the number of bytes used to represent an expression.
But if you’ve moved to MySQL, you may be looking for a function that does the same thing.
In MySQL, the Length() function does basically the same thing that the T-SQL Datalength() function does in SQL Server (and Azure). MySQL’s Length() function returns the length of a string, measured in bytes.
In SQL Server (and Azure), the T-SQL LEN() function returns the number of characters of a specified string expression, excluding trailing blanks.
You provide the string as an argument.
In SQL Server (and Azure), the T-SQL DATALENGTH() function returns the number of bytes used to represent any expression.
For example:
SELECT DATALENGTH('Lit');
Result:
3
In this case, there are 3 bytes in the string Lit.
However, this is a simple example. The results can look a lot different, depending on the data type.