replace a column with another column when column is null in SELECT statement

Question

Here is my dummy Schema in MYSQL:
A column: which is a nullable string
B column: which is a string but its not null

I only want to select A columns but when facing a null, I want it to be replaced with the B column.
How can I do that?
this is my desired output

luna80 · Accepted Answer · 2020-02-27 12:14:49Z

3

coalesce() or

SELECT CASE WHEN A IS NOT NULL THEN A ELSE B END AS value FROM tablename;

answered Feb 27, 2020 at 12:14

luna80

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Gordon Linoff · Accepted Answer · 2020-02-27 12:06:04Z

2

Use coalesce():

select coalesce(a, b) as a
from t;

answered Feb 27, 2020 at 12:06

Gordon Linoff

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Comments

Rajat · Accepted Answer · 2020-02-28 20:52:12Z

0

Or use ifnull, the sound of which makes it easy to remember. Note that it only works for 2 columns/values

select ifnull(a, b) as a
from t;

answered Feb 28, 2020 at 20:52

Rajat

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