FAQ

Frequently asked questions about the Oracle database, SQL and PL/SQL.

When should we use dynamic SQL

When Should We Use Dynamic SQL?

We know that, if there exists a choice between static SQL vs dynamic SQL, static SQL is the way to go. In that case, why and when should we use dynamic SQL?

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Static SQL vs Dynamic SQL

Static SQL vs Dynamic SQL: Which to use?

Static SQL vs dynamic SQL: a comparison on metrics such as security, maintainability and performance, and a rule of thumb for choosing between the two.

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INNER JOIN and OUTER JOIN Explained

Overview of INNER JOIN and OUTER JOIN in Oracle, with examples, memory aids and a further drilldown of INNER JOIN and OUTER JOIN types.

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How to Find out Your Oracle Database Version

Three ways to find out your Oracle database version in SQL and PL/SQL: using V$VERSION, V$INSTANCE, or DBMS_DB_VERSION constants.

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What are CBO and RBO?

Oracle’s inbuilt optimizers – CBO and RBO: how they work to improve query performance, and key differences between cost-based vs rule-based optimization.

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15 Things You Should Know about the ORDER BY Clause

What is the precedence of sorting in a multi-column ORDER BY? How does ORDER BY sort nulls? What does ORDER SIBLINGS BY do? Answers to these questions and more about Oracle’s ORDER BY clause.

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The Difference Between Views and Materialized Views

Key differences between views and materialized views in Oracle, with guidelines to help you decide if a specific scenario needs a view, a materialized view, or neither.

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Thumbnail image for The Difference Between UNION and UNION ALL

The Difference Between UNION and UNION ALL

Both UNION and UNION ALL concatenate the result sets of two separate SQLs. Where they differ is in the way they handle duplicates.

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How to Find Duplicate Records in a Table

Query to find all duplicate records in an Oracle table. Typically required in scenarios where duplicate rows in a table are to be identified and then deleted.

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What is CTAS?

When you want to base your Oracle table structure and data on an existing table, you use CTAS. Learn what that acronym means.

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