Teradata SQL - COALESCE and NULLIF Functions

access_time 11 months ago visibility216 comment 0

COALESCE function in Teradata returns NULL if all arguments evaluate to null; otherwise it returns the value of the first non-null argument. NULLIF is to used evaluate two expressions and returns NULL if the two arguments are equal otherwise if returns the first arguments. IS NULL is used to examine whether one expression is null or not. 

COALESCE code snippet

-- returns 1 
select coalesce(1,2,null);

-- returns 2
select coalesce(null,2,null);

NULLIF code snippet

-- returns d as not equal
select  nullif('d','e');

-- returns null as values are equal
select  nullif('2',2);

-- returns null as values are equal
select  nullif('abc','abc');

IS NULL code snippet

-- returns 2
select  
        case 
            when 'e' is null then '1' 
            else '2' 
        end;

Teradata COALESCE Teradata IS NULL Teradata NULLIF

copyright This page is subject to Site terms.
Like this article?
Share on

Please log in or register to comment.

account_circle Log in person_add Register

Log in with external accounts

Follow Kontext

Get our latest updates on LinkedIn or Twitter.

Want to publish your article on Kontext?

Learn more

More from Kontext

visibility 5373
thumb_up 0
access_time 3 years ago

This page summarize some of the commonly used views in Teradata. In all the views in the following sections, X views are also available though they only return rows that contain information on objects that the requesting database user owns, created, granted privilige on, granted access through the ...

visibility 332
thumb_up 0
access_time 5 months ago

Teradata FastExport is a command utility tool that can transfer large amount of data from Teradata database to a file.  One of the commonly used scenarios is to export data from a table or view to a text file and then load the export file into a different server.  Follow the following ...

visibility 16539
thumb_up 0
access_time 7 years ago

In this article, I am going to introduce how to install Teradata Express in virtual machines in Windows. 1) Download VMware Player for Windows 32-bit and 64-bit from the following link (version 6.0): https://my.vmware.com/web/vmware/free#desktop_end_user_computing/vmware_player/6_0 This is ...