To make the column null for all the records we first have to make the table accept NULL value by updating the structure of the table.ĪLTER TABLE `student3` CHANGE `class` `class` VARCHAR( 10 )ĬHARACTER SET latin1 COLLATE latin1_swedish_ci NULL DEFAULT ''Īfter this change we can add NULL value to the record. We can't change the value of the column ( class here ) if the property is set to NOT NULL for the column. We can make all the class data ( or column ) equal to NULL by updating the record like this Now we will get all the records without having NULL value in class column SELECT * FROM `student3` WHERE class IS NOT NULL Similarly we can display all the records which do not have null value for the class. This will display all the records which have NULL value for class column.
← SQL dump of student3 table SELECT* FROM`student3` WHERE class IS NULL
#Mysql insert sql where record is null install
You can download and install a copy of this table to test in your database. Here for the absent students, we will use NULL, as no data exist for these students and at the same time we can't use 0 marks for them.įor all our examples we have modified our student table by making class and mark column to accept null and changed the data to add some null values. NULL : In an exam some students got 0 mark and some have not appeared in the exam.
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