Database Management Systems
If you ever find yourself wanting only the first part of a string, or the last part of it, this article might help.
This article is specific to SQL Server, but the functionality is pretty common across most/all database management systems, not to mention most programming languages.
When working with SQL Server, you can use theT-SQL LEFT() and RIGHT() functions to return any given number of characters from the left or right of a string.
When working with MySQL databases, you might occasionally find yourself needing to select only a certain number of characters from the left or right of a string. In such cases, you can use the LEFT() and RIGHT() functions to do just that.
Here’s the syntax for both of these functions:
LEFT(str,len) RIGHT(str,len)
Where str is the string that contains the substring you need to return, and len is the number of characters from the left you want returned.
Starting from SQL Server 2008, the REVERSE() function can be used to reverse the order of a string. That is, it returns the characters in the string in reverse order.
Here’s the syntax:
REVERSE ( string_expression )
Where string_expression is an expression of a string or binary data type. It can be a constant, variable, or column of either character or binary data.
Occasionally when working with MySQL databases, you might find yourself needing to add multiple space characters to a string.
Maybe you need to pad a string by adding leading or trailing spaces. Or maybe you need to replace a single space within the string with many spaces. Either way, MySQL has the SPACE() function to help you.
The SPACE() function is an easy way for you to return as many space characters as you need.
When working with databases and the associated data, sometimes you need to insert a space when joining two strings together, or sometimes you need to replace a character with a space.
And then sometimes you need to insert multiple spaces. Here are 3 ways to return a string of multiple spaces in SQL Server using T-SQL.
MySQL has a TRIM() function that enables you to remove leading and/or trailing whitespace from a string.
You can also use it to remove other specified characters from either side (or both sides) of the string.
This article explains how to remove specified leading/trailing characters from the string.
MySQL has the LTRIM() function that enables you to remove leading whitespace from a string (space at the start of the string).
MySQL also has the TRIM() function that enables you to remove leading space, trailing space (at the end), space from both sides, or to remove other specified characters from either side (or both sides) of the string.
This article demonstrates how to remove leading space using each of these functions.