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SQL INTERVIEW QUESTION & ANSWERS
|56.||What is the difference between SQL and PL/SQL?|
|SQL is a declarative language. PL/SQL is a procedural language that makes up for all the missing elements in SQL.|
|57.||What clause is used to order data when creating a view?|
|The GROUP BY clause functions in a view much as the ORDER BY clause (or GROUP BY clause) does in a regular query.|
|58.||What is a trigger?|
|A trigger is a schema object that is invoked automatically when a specified data modification is made. Once invoked, the trigger takes a predefined action, which is specified in one or more SQL statements.|
|59.||What are the two primary differences between procedures and functions?|
|Procedures are invoked by using a CALL statement, and they support input and output parameters.
Functions are invoked as a value in an expression, and they support input parameters only.
|60.||What are the three types of outer joins?|