How to check if a column has all null values in a table? snowflake sql

Question

I would like to see if in my table there exists a column where the entirety of its rows are null.

SELECT * FROM yourTableName 
  WHERE yourSpecificColumnName IS NULL 

-> this will only return the values that are null but i wont know if yourSpecificColumnName is entirely null throughout the table

Answer 1

Using COUNT combined with HAVING :

COUNT

Returns either the number of non-NULL records for the specified columns , or the total number of records.

SELECT 'Entire_column_is_empty'
FROM yourTable
HAVING COUNT(yourSpecificColumnName) = 0;

or QUALIFY :

SELECT *
FROM yourTable
QUALIFY COUNT(yourSpecificColumnName) OVER() = 0;

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Alternative approach:

SELECT 'Entire_column_is_empty'
FROM yourTable
HAVING MIN(yourSpecificColumnName) = MAX(yourSpecificColumnName);