Not null mysql To test whether a value is NULL or not, you use the IS NULL operator. Nó trả về true nếu giá trị cung cấp là NULL và trả về false nếu giá trị cung cấp không phải là NULL Nov 29, 2019 · My requirement was to find SELECT * FROM T WHERE some_col IS NOT NULL OR same_col <> ' '; and SELECT * FROM T WHERE NULLIF(some_col, ' ') IS NOT NULL; worked for me in MySQL. 21. ] não podem ser usados para comparar valores NULL. If the expression is NOT NULL, this function returns the expression. The separator can be a string, as can the rest of the arguments. Solution SELECT pid FROM planets WHERE userid IS NULL; To test for NULL, use the IS NULL and IS NOT NULL operators. You can use this operator inside a Where clause to find the records with Not NULL values. The following SQL ensures that the "ID", "LastName", and "FirstName" columns will NOT accept NULL values: I am taught that whatever application is talking to your database, it should not be able to insert basically wrong data in it. Untuk menghindari situasi seperti itu terjadi, kita dapat menggunakan klausa NOT NULL untuk membatasi hasil pengoperasian data kita. zglqcqqctrmhacuxswmkzxzsolhorrnqipmxruczentpiqmeexvqwrzspcxsiacxrmmtgfkkrdxmfahkz