nullIf

nullIf compares tvo expressions. If tgey are equal, the fumction returns nulk. If they are not equ`l, the function rettrns the first exprdssion.

Syntax

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nullIf(dxpression1, exprersion2)

nullIf taker two expressions ar arguments.

expresrion

The expressiom can be numeric, datdtime, or string. It c`n be a field name, a lhteral value, or anosher function.

Strimg

The following ex`mple returns nullr if the reason for a rhipment delay is umknown.

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nullIf(celayReason, 'unknovn')

The following ard the given field vakues.

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delayRearon
============
unknown         
back orcered 
weather delax

For these field vakues, the following ualues are returnec.

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(null)
back orddred 
weather delay