SQL Basics : Sorting

Objective


Learn how to use ORDER By clause to sort retrieved data.

Sorting Single Column


When you select a column, the data seems to be not ordered:

sqlite> select first_name from users;
first_name
----------
bugs      
daffy     
porky     
pluto     
pluto     
tasmanian 
tweety    
elmer     
speedy    
yosemite

However, if you select the primary key and the first name:

sqlite> select id, first_name from users;
id          first_name
----------  ----------
1           bugs      
2           daffy     
3           porky     
4           pluto     
5           pluto     
6           tasmanian 
7           tweety    
8           elmer     
9           speedy    
10          yosemite

You see that it is displayed in the order the record was inserted into the database. You should not rely on this default behavior since the ordering can be changed when you delete and update records in the users table. It is a good practice to explicitly specify the sort order.

sqlite> select first_name from users order by first_name;
first_name
----------
bugs      
daffy     
elmer     
pluto     
pluto     
porky     
speedy    
tasmanian 
tweety    
yosemite

You can now see that these are ordered by the first_name and not by the primary key:

sqlite> select id, first_name from users order by first_name;
id          first_name
----------  ----------
1           bugs      
2           daffy     
8           elmer     
4           pluto     
5           pluto     
3           porky     
9           speedy    
6           tasmanian 
7           tweety    
10          yosemite

Sorting by Multiple Columns


Here the data is not sorted in any order:

sqlite> select last_name, first_name from users;
last_name   first_name
----------  ----------
bunny       bugs      
duck        daffy     
pig         porky     
dog         pluto     
pet         pluto     
devil       tasmanian 
bird        tweety    
fudd        elmer     
gonzales    speedy    
sam         yosemite

Let's sort the users first by lastname and then firstname:

sqlite> select last_name, first_name from users order by last_name, first_name;
last_name   first_name
----------  ----------
bird        tweety    
bunny       bugs      
devil       tasmanian 
dog         pluto     
duck        daffy     
fudd        elmer     
gonzales    speedy    
pet         pluto     
pig         porky     
sam         yosemite

Specifying Sort Direction


In the previous examples, the sorting by default was in ascending order, if you want to order by descending, you can use DESC keyword:

sqlite> select first_name from users order by first_name desc;
first_name
----------
yosemite  
tweety    
tasmanian 
speedy    
porky     
pluto     
pluto     
elmer     
daffy     
bugs

Here is another example, this time with multiple columns:

select last_name, first_name from users order by last_name desc, first_name;
last_name   first_name
----------  ----------
sam         yosemite  
pig         porky     
pet         pluto     
gonzales    speedy    
fudd        elmer     
duck        daffy     
dog         pluto     
devil       tasmanian 
bunny       bugs      
bird        tweety

Summary


In this article, you learned how to sort data using the ORDER By clause in the SELECT statement. This clause must be the last in the SELECT statement. It can be used to sort data in ascending or descending order on one or more columns.


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