Unlike Microsoft's database products, Oralce automatically replaces the '' empty String to null
So the following code you may consider a different result.
CREATE TABLE SUPPLIERS (Supplier_IDNumber, Supplier_Name Varchar2);
Next, We'll Insert Two Records Into this Table.
INSERT INTO Suppliers (Supplier_ID, Supplier_Name) Values (10565, NULL);
INSERT INTO Suppliers (Supplier_ID, Supplier_Name) Values (10567, ');
SELECT * from Suppliers where supplier_name = ''; // SQL Server Returns the second record, and Oracle returns to empty.
He will put NULL equivalence ''
So SELECT * from Suppliers where support_name is null;
Returns all non-empty records, including null and ''
Microsoft also has a KB Q225070 PRB: Oracle Servers Convert Empty Strings To Null
