Sql check column is null or empty It is wiser to use t. To find all tracks whose composers are unknown, you use the IS NULL operator as shown in the following query: SELECT Name, Composer FROM tracks WHERE Composer IS NULL ORDER BY Name; Code language: SQL (Structured Query Language) (sql) Here is the partial output Mar 18, 2014 · I noticed that sometimes IS NOT NULL is not applied to string only columns with empty values (''). The following code snippet uses isnull function to check is the value/column is null. EDIT. – Justin Cave Commented Mar 11, 2014 at 21:45 Apr 11, 2009 · To be clear, cardinality "returns the total number of elements in the array, or 0 if the array is empty", which is what you would expect of array_length, but the later returns NULL when length is zero. The SQL IS NULL condition is used to test for a NULL value (similar to the NULL definition above Oct 12, 2017 · I have table field of type DateTime with allow null in SQL server database. The other thing to note is that NULL and empty are two different things, they are not the same. When one tried to process a data table with 0 records but with column information it will throw exception. I use query: SELECT * FROM Farm f WHERE f. The SQL IS NULL is an operator that tests for NULL (or empty) values in a column. mvtwghnxchebtxngvvjdvhgjkiurfyggslccjpdprbkvmzgptxeufzmjcycazvtnyfdd