Page 53 - Modular_V2.0_SQL_Flipbook

Let us consider another example of Table - FRESH

Table-FRESH

O_number O_amt O_name O_date Customer_code
5100 100000 Okra 2025-01-21 101
5101 125000 Brinjals 2025-01-19 107
5102 90000 Tomatoes 2025-01-10 106
5103 88000 Peas 2024-12-11 103

SELECT O_number, O_amt, O_date, Customer_code FROM FRESH

WHERE O_amt = (SELECT MAX(O_amt) FROM FRESH WHERE O_date >'2025-01-10');
The above query shows the use of MAX function and relational operator in a subquery. The given
query will generate the output for the customer having maximum O_amt, when purchase is made
after 2025-01-10.

Output:
+----------+--------+------------+---------------+
| O_number | O_amt | O_date | Customer_code |
+----------+--------+------------+---------------+
| 5101 | 125000 | 2025-01-10 | 107 |
+----------+--------+------------+---------------+
JOINS

A JOIN clause is used to combine rows from two or more tables based on a related column between
them. SQL joins are essentially the tools that efficiently allows us to extract meaningful information
from multiple tables. They help the programmer by simplifying the process of making sense of
many interlinked database tables and enable them to extract the required information based on the
situation, thus producing the desired solution. Let’s understand how joins work with the following
example:

Let us consider the following tables:
Table-STUDENTS

Stu_id Stu_name Age Class Marks
101 Rahim 18 XII 87
102 Raja 19 XII 66
103 Riya 18 XII 55

Table-FEE
Stu_id Fees Fine Transport

101 12000 100 2000
102 13000 500 3000
103 12000 100 5000

SELECT Stu_name, Age, Fees, Transport FROM STUDENTS, FEE WHERE STUDENTS.
Stu_id = FEE.Stu_id;
JOIN Condition

51
Advanced Features of MySQL