Structured-Query-Language-SQL-/Update Records in Table SQL.txt at main · Unique982/Structured-Query-Language-SQL- · GitHub

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// Update Records in Table.
The Update statement is used existing records in a table.
syntax: UPDATE table_name SET column1 = value1, column2=value2 WHERE some_column = some_value;
ex:  UPDATE student_reg SET name ='RAM',fees=100000.23 WHERE s_id =101;
mysql> select * from student_reg;
+------+---------+---------+------------+-----------+------+
| s_id | name    | address | dob        | fees      | id   |
+------+---------+---------+------------+-----------+------+
|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | NULL |
|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL |
|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL |
|  104 | BIMAl   | KTM     | NULL       |   1001.23 | NULL |
|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL |
|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL |
+------+---------+---------+------------+-----------+------+

// example 2nd file data
ex:UPDATE student_reg SET name ='RAM',id=1001 WHERE s_id =101;


mysql> select * from student_reg;
+------+---------+---------+------------+-----------+------+
| s_id | name    | address | dob        | fees      | id   |
+------+---------+---------+------------+-----------+------+
|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | 1001 |
|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL |
|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL |
|  104 | BIMAl   | KTM     | NULL       |   1001.23 | NULL |
|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL |
|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL |
+------+---------+---------+------------+-----------+------+

Ex:  UPDATE student_reg SET fees = 100200 WHERE s_id = 104;
Output:select * from student_reg;
+------+---------+---------+------------+-----------+------+
| s_id | name    | address | dob        | fees      | id   |
+------+---------+---------+------------+-----------+------+
|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | 1001 |
|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL |
|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL |
|  104 | BIMAl   | KTM     | NULL       | 100200.00 | NULL |
|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL |
|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL |
+------+---------+---------+------------+-----------+------+


Note: WHERE is necessary otherwise all records will be replace with given value.