Check out example codes for "left joing sql". It will help you in understanding the concepts better.

Code Example 1

/*Two tables: CUSTOMERS table and ORDERS table.
ORDERS table contains STATUS attribute.*/
SELECT 
    customers.customerNumber, 
    customerName, 
    orderNumber, 
    status
FROM
    customers
LEFT JOIN orders ON 
    orders.customerNumber = customers.customerNumber;

Code Example 2

left join or left outer join

Code Example 3

SELECT column_name(s)

FROM table1

LEFT JOIN table2
 ON table1.column_name = table2.column_name;

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