SQL Server 2019

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CREATE TABLE t(id INT PRIMARY KEY, democol1 INT, democol2 INT);

INSERT INTO t
VALUES (1, NULL, 2),(2,3,4)
2 rows affected

SELECT 
  FORMATMESSAGE('SELECT col = ''%s.%s.%s'' FROM %s.%s HAVING COUNT(*) != COUNT(%s)', 
     QUOTENAME(TABLE_SCHEMA),
     QUOTENAME(TABLE_NAME),
     QUOTENAME(COLUMN_NAME),
     QUOTENAME(TABLE_SCHEMA),
     QUOTENAME(TABLE_NAME),
     QUOTENAME(COLUMN_NAME)
  )
FROM INFORMATION_SCHEMA.COLUMNS
WHERE IS_NULLABLE = 'YES'

(No column name)

SELECT col = '[dbo].[t].[democol1]' FROM [dbo].[t] HAVING COUNT(*) != COUNT([democol1])

SELECT col = '[dbo].[t].[democol2]' FROM [dbo].[t] HAVING COUNT(*) != COUNT([democol2])

SELECT col = '[dbo].[t].[democol1]' FROM [dbo].[t] HAVING COUNT(*) != COUNT([democol1])
SELECT col = '[dbo].[t].[democol2]' FROM [dbo].[t] HAVING COUNT(*) != COUNT([democol2])

col

[dbo].[t].[democol1]

Warning: Null value is eliminated by an aggregate or other SET operation.

col