Having completed our series on Top SQL Query Mistakes last week, it's time to take a page from the Monty Python playbook and move on to something completely different. And that something is why database developers and administrators should consider using third-party database administration tools (DBMT) to fill the gaps left by the major database manufacturers. Regardless of price, all 3rd party DBMT provide functionality that fulfills the needs of the general DBA community by either complimenting or replacing database manufacturers' tool sets. Today's blog will highlight just a few of the benefits provided by 3rd party DBMT.

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Predicate Evaluation Order

Just before Part 3 of this series, we took a brief pause to talk about Predicates in SQL, as they factored into mistakes related to Outer Joins. In this final installment of this series on Top SQL Query Mistakes, predicates will once again enter the picture, as we examine how predicate evaluation order can cause seemingly well constructed queries to fail with errors.

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Breaking Subqueries

In this series on Top SQL Query Mistakes, we've seen several examples of SQL queries that look perfectly solid on first inspection, but can lead to erroneous results and/or performance degradation. Last week, learned how the placement of predicates can adversely affect query execution - particularly in outer joins. Today's installment will focus on subqueries, and how they can break an SQL statement when changes are made to any of its underlying tables.

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Outer Joins and Cartesian Products

In this series on Top SQL Query Mistakes, we've been exploring how seemingly intuitive ways of constructing SQL queries can result in anti-patterns that lead to erroneous results and/or performance degradation. Last week, we took a break from the series to talk about Predicates in SQL. In this installment, we'll be learning how their placement can adversely affect query execution - particularly in outer joins.

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