I have a table with three fields, FirstName, LastName and Email. Here's some dummy data: … Now, if I do: … Vitals for Joe is null, as there is a single null field. How do you overcome this behaviour?
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!
Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
If I have this - tadd is the Address table: … Is there a way to exclude the apt_number if it doesn't exist? I was thinking of: … But it will return only those rows with apt_number...
1 UNION ALL SELECT NULL,concat(TABLE_NAME) FROM information_schema.TABLES WHERE table_schema='database1'
First, it’s important to know what a NULL is in SQL. A NULL in SQL simply means no value exists for the field.
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct
In one of my MySQL queries, it can happen from time to time that in the results there is the one or the other NULL value, because the corresponding cell has not yet been added to the database. To nevertheless be able to process the values in my PHP script, I would like to make MySQL return the...
Что такое NULL? Наряду с множеством типов данных в БД, NULL стоит особняком. NULL означает отсутствие значения.
mysql> SELECT NULL, 1+NULL, CONCAT('Invisible',NULL); To search for column values that are NULL, you cannot use an expr = NULL test. The following statement returns no rows, because expr = NULL is never true for any expression: mysql> SELECT * FROM my_table WHERE phone = NULL