Join

SELF JOIN

A SELF JOIN is a join of a table to itself. Here are two ways in which SELF JOIN may be accomplished Example 2: this example uses the same table twice on the from selector SELECT e1.last_name||’ works for ‘||e2.last_name“Employees and Their Managers”FROM employees e1, employees e2WHERE e1.manager_id = e2.employee_idAND e1.last_name LIKE ‘R%’ORDER BY e1.last_name; […]

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UNION ALL Join SQL

What is a UNION ALL Join? A UNION ALL Join is a powerful technique that allows you to combine the results of two or more SELECT statements into a single result set. Unlike traditional joins, UNION ALL Join does not require matching keys or conditions between tables. Instead, it vertically stacks the results of individual

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DELETE DATA SQL

Deleting all records is similar to the TRUNCATE funciton Basic syntax for deleting records. DELETE FROM table_name WHERE condition; Deleting All Records: To delete all records from a table, you can use a simple DELETE statement without a WHERE clause: Delete with JOIN: You can also use the DELETE statement with JOIN to delete records

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NATURAL JOIN Oracle

Natural joins in SQL automatically link tables based on columns with the same name. These joins simplify queries by eliminating the need to list matching columns explicitly. The syntax for a natural join is straightforward: SQL automatically identifies common column names between tables and performs the join. NATURAL JOINS HAVE PROS AND CONS Pros Conciseness:

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