Tag: functions

How to Insert a String into another String in SQL Server using STUFF()

Posted on by Ian

In SQL Server, you can use the T-SQL STUFF() function to insert a string into another string. This enables you to do things like insert a word at a specific position. It also allows you to replace a word at a specific position.

Here’s the official syntax:

STUFF ( character_expression , start , length , replaceWith_expression )
  • character_expression is the original string. This can actually be a constant, variable, or column of either character or binary data.
  • start specifies the start position (i.e. where the new string will be inserted).
  • length is how many characters are to be deleted from the original string.
  • replaceWith_expression is the string that’s being inserted. replaceWith_expression can be a constant, variable, or column of either character or binary data.

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How to Insert a String into another String in MySQL using INSERT()

Posted on by Ian

In MySQL, you can use the INSERT() function to insert a string into another string.

You can either replace parts of the string with another string (e.g. replace a word), or you can insert it while maintaining the original string (e.g. add a word). The function accepts 4 arguments which determine what the original string is, the position with which to insert the new string, the number of characters to delete from the original string, and the new string to insert.

Here’s the syntax:

INSERT(str,pos,len,newstr)

Where str is the original string, pos is the position that the new string will be inserted, len is the number of characters to delete from the original string, and newstr is the new string to insert.

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What is T-SQL?

Posted on by Ian

Transact-SQL, often abbreviated to T-SQL or even TSQL, is Microsoft’s and Sybase’s proprietary extension to SQL. Transact-SQL expands on the SQL standard to include extra features that aren’t included in the SQL standard.

Here’s an example of a simple T-SQL statement:

CREATE DATABASE Movies;

This is as simple as a T-SQL example could get. This creates a new database called Movies.

However, T-SQL provides for other options to be included in this statement, such as where the database files should be located, the size of those files, what their maximum size should be, and more.

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The Difference Between FIELD() and FIND_IN_SET() in MySQL

Posted on by Ian

MySQL includes a FIELD() function and a FIND_IN_SET() function that both return the position of a string within a list. However, these functions work slightly differently to each other.

The main difference between these two functions is this:

  • FIND_IN_SET() returns the index position of a string within a string list.
  • FIELD() returns the index position of a string within a list of arguments.

So one function searches a string list, and the other function searches a list of arguments.

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How to Return the Position of a List Item in MySQL

Posted on by Ian

In MySQL, you can use the FIND_IN_SET() function to return the index of a given list item within a string list (for example ‘item1, item2, item3,…’).

The function takes two arguments; the string to find, and the list to search.

The syntax goes like this:

FIND_IN_SET(str,strlist)

Where str is the the string you’re looking for, and strlist is the string list to search through.

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CHARINDEX() vs PATINDEX() in SQL Server – What’s the Difference?

Posted on by Ian

In SQL Server, you can use either the CHARINDEX() function or the PATINDEX() function to find a string within a string. These are Transact-SQL string functions, and they’re also available on Azure databases.

On the surface, these functions appear to do exactly the same thing, and in many cases, you could use whichever you prefer to use.

However, there a a couple of distinctions that could dictate which function you decide to use in certain scenarios. These can be summarized by the following:

  • PATINDEX() allows you to use wildcard characters to search for patterns. CHARINDEX() doesn’t.
  • CHARINDEX() accepts a third argument which allows you to specify the start position of the search. PATINDEX() doesn’t.

More detail on these points below.

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How to Find a String within a String in SQL Server

Posted on by Ian

In SQL Server, you can use the T-SQL CHARINDEX() function or the PATINDEX() function to find a string within another string. Here’s a quick overview of each function.

The CHARINDEX() Function

This function accepts 3 arguments; the string to find, the string to search, and an optional start position.

The CHARINDEX() syntax goes like this:

CHARINDEX ( expressionToFind , expressionToSearch [ , start_location ] )

Where expressionToFind is the expression you want to find in the other string, and expressionToSearch is the other string. The optional start_location can be used to specify a position within expressionToSearch for which to start searching.

Note that only the position of the first occurrence is returned.

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What’s the SQL Server Equivalent of ELT() in MySQL?

Posted on by Ian

In MySQL, you can use the ELT() function to return an item from a specified position in a list. SQL Server has a similar function, but with a different name.

In SQL Server, the CHOOSE() function does basically the same thing that the ELT() function does in MySQL. To be more precise, CHOOSE() is actually a Transact-SQL function, so it can also be used in Azure databases.

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How to Find a List Item at a Specified Position in MySQL

Posted on by Ian

In MySQL, you can use the ELT() function to return a list item at a given position in the list.

The syntax goes like this:

ELT(N,str1,str2,str3,...)

Where N is the position of the item you want to return, and str1,str2,str3,... is the list.

Example

Here’s an example:

SELECT ELT(3, 'Marge', 'Homer', 'Bart') AS 'Who is at 3?';

Result:

+--------------+
| Who is at 3? |
+--------------+
| Bart         |
+--------------+

In this case we specify that we want to return the 3rd item in the list (because the first argument is 3) . And in this case the list is 'Marge', 'Homer', 'Bart', so the 3rd item is Bart. Continue reading →