関連ワード:  sql query to check column is null    sql query to check column is empty    sql query to check if any column is null    sql query to check column not null    sql query to check field is not null    sql query to check column value is not null    sql query to find columns with null values    sql query to check if column is null or empty    sql query check if field is null    sql query to check if column is not null or empty