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Make sure your AUTO_INCREMENT is not out of range. In that case, set a new value for it with: ALTER TABLE table_name AUTO_INCREMENT=100 -- Change 100 to the desired number Explanation. AUTO_INCREMENT can contain a number that is bigger than the maximum value allowed by the
B.3.4.3 Problems with NULL Values. The concept of the NULL value is a common source of confusion for newcomers to SQL, who often think that NULL is the same thing as an empty string ''. This is not the case. For example, the following statements are completely different: mysql> INSERT INTO my_table (phone) VALUES (NULL); mysql> INSERT INTO my ...
In this tutorial, you will learn how to work with MySQL NULL values and use some useful functions to deal with the NULL values effectively
31 lip 2024 · When creating tables in MySQL we can specify whether a column allows the NULL values or not. By default, columns can contain NULL values unless specified otherwise. In MySQL, NULL represents a missing, unknown, or undefined value. It is not equivalent to the empty string (”) or zero (0).
NULL. Two NULL values are regarded as equal in a GROUP BY. When doing an ORDER BY, NULL values are presented first if you do ORDER BY ... ASC and last if you do ORDER BY ... DESC.
9 mar 2023 · To account for null values, we can use the null-safe equal operator <=>, also known as the “spaceship operator.”. This operator considers null and another null value as equal. To compare a column with a null value, we can use the is null or is not null operators.
The IS NOT NULL operator is used to test for non-empty values (NOT NULL values). The following SQL lists all customers with a value in the "Address" field:
