Answers for "how to use union sql"

sql union

-- UNION: distinct values (slower)
SELECT emp_name AS name from employees
UNION       
SELECT cust_name AS name from customers;

-- UNION ALL: keeps duplicates (faster)
SELECT emp_name AS name from employees
UNION ALL      
SELECT cust_name AS name from customers;

sql union

Combines the results from 2 or more SELECT statements and returns only
distinct values.
Example: Returns the cities from the events and subscribers tables.
SELECT city FROM events
UNION
SELECT city from subscribers;

union SQL

SQL> SELECT  ID, NAME, AMOUNT, DATE
   FROM CUSTOMERS
   LEFT JOIN ORDERS
   ON CUSTOMERS.ID = ORDERS.CUSTOMER_ID
UNION
   SELECT  ID, NAME, AMOUNT, DATE
   FROM CUSTOMERS
   RIGHT JOIN ORDERS
   ON CUSTOMERS.ID = ORDERS.CUSTOMER_ID;