Setting Null in MySQL
In this tutorial, we aim to explore how to set NULLthe value in MySQL.
If there is no value, then the specific table field in MySQL has to be updated NULL. This NULLvalue addition helps in data storage, accessibility, and analysis.
You may want to set specific fields of your validation form to true if the user has no input NULL. UPDATE TABLEMySQL helps with this with the help of the statement.
Let us understand how this method works.
Before we begin, let's create a dummy dataset to work with a table student_details, with a few rows in it.
-- create the table student_details
CREATE TABLE student_details(
stu_id int,
stu_firstName varchar(255) DEFAULT NULL,
stu_lastName varchar(255) DEFAULT NULL,
primary key(stu_id)
);
-- insert rows to the table student_details
INSERT INTO student_details(stu_id,stu_firstName,stu_lastName)
VALUES(1,"Preet","Sanghavi"),
(2,"Rich","John"),
(3,"Veron","Brow"),
(4,"Geo","Jos"),
(5,"Hash","Shah"),
(6,"Sachin","Parker"),
(7,"David","Miller");
Setting Null Values in MySQL
The basic syntax of the technique can be illustrated as follows.
UPDATE name_of_the_table SET column_name = NULL WHERE <condition>;
Based on certain conditions, let us NULLassign values to the columns student_detailsof a table stu_lastName.
UPDATE student_details SET stu_lastName = NULL WHERE stu_id IN (1,2,3);
The output of the above code block can be illustrated with the following query.
SELECT * from student_details;
Output:
stu_id stu_firstName stu_lastName
1 Preet NULL
2 Rich NULL
3 Veron NULL
4 Geo Jos
5 Hash Shah
6 Sachin Parker
7 David Miller
As shown in the code block above, students stu_idwhose is 1, 2or 3have been assigned their lastName NULLvalue.
Therefore, with the help of UPDATEstatement, we can effectively set null value for a specific field in MySQL table.
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