FROM clause is a mandatory clause in SELECT expression. It specifies the tables from which data is to be retrieved.
FROM table_name... Expressions...
Let's take an example to explain how to use FROM clause to retrieve data from one table. Consider a table "customers".
CREATE TABLE "CUSTOMERS" ( "NAME" VARCHAR2(4000), "AGE" NUMBER, "SALARY" NUMBER, "STATE" VARCHAR2(4000) ) /
Execute this query:
SELECT * FROM customers WHERE salary >= 20000 ORDER BY salary ASC;
Inner Join example:
Let's take two tables "suppliers" and "order1".
Execute the following query:
SELECT suppliers.supplier_id, suppliers.supplier_name, order1.order_number FROM suppliers INNER JOIN order1 ON suppliers.supplier_id = order1.supplier_id;