How to check if a column is empty or null using SQL query select statement

Question

How do I check if a column is empty or null using a SQL select statement   For instance  if I want to check   select   from UserProfile WHERE PropertydefinitionID in  40  53  and PropertyValue is null or empty

User · Answer

Here s a slightly different way   SELECT   FROM UserProfile WHERE PropertydefinitionID in  40  53    AND  LEN ISNULL PropertyValue        0

User · Answer

Does this do what you want   SELECT   FROM UserProfile WHERE PropertydefinitionID in  40  53    AND      PropertyValue is NULL         or PropertyValue

User · Answer

An answer above got me 99  of the way there  thanks Denis Ivin    For my PHP   MySQL implementation  I needed to change the syntax a little   SELECT   FROM UserProfile WHERE PropertydefinitionID in  40  53  AND  LENGTH IFNULL PropertyValue        0    LEN becomes LENGTH and ISNULL becomes IFNULL

User · Answer

If you want blanks and NULLS to be displayed as other text  such as  Uncategorized  you can simply say     SELECT ISNULL NULLIF  PropertyValue         Uncategorized   FROM UserProfile   The above answers the main question very well   This answer is an extension of that and is of value to readers

User · Answer

Here is my preferred way to check for  if null or empty    SELECT    FROM UserProfile  WHERE PropertydefinitionID in  40  53   AND NULLIF PropertyValue      is null   Since it modifies the search argument  SARG  it might have performance issues because it might not use an existing index on the PropertyValue column

User · Answer

select isnull nullif CAR OWNER TEL        NULLLLL    PHONE from TABLE   will replace CAR OWNER TEL if empty by NULLLLL  MS SQL

[tsql] How to check if a column is empty or null using SQL query select statement?

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