What is union in 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;

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;

Source: tutorialspoint.com

What is union in sql

UNION:
COMBINES THE RESULT OF 2 QUERY AND
REMOVES DUPLICATE ROWS AND
SORTS BY FIRST COLUMN

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