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We can also use the wildcards (_and %) with the SELECT command to specify conditions. The _ wildcard
denotes a single character, on the other hand the % wildcard denotes the multiple characters:
SELECT FirstName, Marks FROM Student WHERE LastName like 'K%';
+-----------+-------+
| FirstName | Marks |
+-----------+-------+
| Divya | 450 |
| Aadarsh | 450 |
+-----------+-------+
SELECT Marks FROM Student WHERE FirstName like 'D%';
+-------+
| Marks |
+-------+
| 450 |
+-------+
UPDATING RECORDS IN A TABLE
Sometime, you may need to change the detail inserted into a table. In that case, the UPDATE command
will work. The syntax of the UPDATE command is:
UPDATE table_name SET field_change=value WHERE field_criteria=value;
Let us change the marks of the student having 10002 as StudentID from 480 to 485 by using the
following command:
UPDATE Student SET Marks = 485 where StudentID = 10002;
+-----------+-----------+----------+-------+
| StudentID | FirstName | LastName | Marks |
+-----------+-----------+----------+-------+
| 10001 | Amit | Sharma | 450 |
| 10002 | Divya | Kaushik | 485 |
| 10003 | Aadarsh | Kumar | 450 |
+-----------+-----------+----------+-------+
REMOVING RECORDS FROM A TABLE
The DELETE command is used to remove records from a table. The DELETE command can be used in
two ways:
Without WHERE clause
With the WHERE clause
We can remove a specific record by using the WHERE clause with the DELETE command. If we use the
DELETE command without the WHERE clause, it will remove all the records from a table. Let us use the
DELETE command to remove the record of a student whose LastName is Kumar:
DELETE FROM Student WHERE LastName="Kumar";
To remove all the records, following command is used:
DELETE FROM Student;
Introduction to MySQL 133

