Author: Ian

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.

Continue reading →

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.

Continue reading →

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.

Continue reading →

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.

Continue reading →

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.

Continue reading →

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.

Continue reading →

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 →

How to Find a List Item at a Specified Position in SQL Server

Posted on by Ian

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.

Example

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.
Continue reading →

How to Return an Argument’s Position within a List of Arguments in MySQL

Posted on by Ian

In MySQL, you can use the FIELD() function to return the position of a given string or number within a list of arguments. The function returns the index (position) of the first argument in the list of subsequent arguments.

The syntax goes like this:

FIELD(str,str1,str2,str3,...)

Where str is the item you want to find, and str1,str2,str3,... is the list you’re searching through.

Here’s an example:

SELECT FIELD('Homer', 'Marge', 'Homer', 'Bart') AS 'Where is Homer?';

Result:

+-----------------+
| Where is Homer? |
+-----------------+
|               2 |
+-----------------+

In this example, the list is: 'Marge', 'Homer', 'Bart' and we’re searching for the string Homer within that list. And because Homer is the 2nd item in the list of arguments, the result is 2.

Continue reading →