Why should you care?

Almost every screen in banking and ERP is a SELECT under the hood — accounts, balances, tickets, invoices.

See it live — copy this example

Run these statements in SQL Developer or SQL*Plus against your lab PDB. Prefer a practice user — not SYS — for application SQL.

-- OracleCore sample
CREATE TABLE customers (
  customer_id NUMBER PRIMARY KEY,
  full_name   VARCHAR2(100) NOT NULL,
  city        VARCHAR2(50),
  balance     NUMBER(12,2) DEFAULT 0
);

INSERT INTO customers VALUES (1, 'Asha Rao', 'Bengaluru', 25000);
INSERT INTO customers VALUES (2, 'Vikram Shah', 'Mumbai', 18000);
COMMIT;

SELECT customer_id, full_name, balance
FROM customers
WHERE city = 'Bengaluru'
ORDER BY balance DESC;

What happened?

• CREATE TABLE defines columns.
• INSERT adds rows.
• COMMIT saves them.
• SELECT filters Bengaluru customers and sorts by balance.

Practice next

1. Run the CREATE/INSERT/COMMIT in SQL Developer.
2. Run the SELECT.
3. Change the city filter to Mumbai.
4. Add a third customer.
5. Select only full_name and city.

Remember

SELECT reads rows; WHERE filters; ORDER BY sorts. COMMIT makes DML visible to others. Practice on small tables first.

Branch customer list

Branch manager needs Bengaluru customers sorted by balance for a campaign.

Outcome: One clear SELECT replaces a messy Excel export.