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Tag Archives: SQL

How to Find the Closest Subset Sum with SQL

I’ve stumbled upon this very interesting question on Stack Overflow, recently. Its title is: [How to] compare a number with sum of subset of numbers In this article, we’ll compare the user’s imperative approach to the extremely elegant (Oracle) SQL approach. We’ll be making use of any combination of these awesome SQL features:   Window functions FIRST and LAST functions, ...

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Leveraging new features in Drill 1.2 – ANSI SQL Analytic/Window functions

Today we are very excited to announce the latest version of Apache Drill, 1.2,) as part of the MapR distribution. Drill 1.2 packages for MapR can be downloaded http://doc.mapr.com/display/MapR/Apache+Drill+on+MapR You can experiment with the release using MapR sandbox and various hands on tutorials at https://www.mapr.com/products/mapr-sandbox-hadoop/download-sandbox-drill Apache Drill has been gaining significant user adoption and community momentum since its initial Beta ...

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jOOQ Tuesdays: Markus Winand is on a Modern SQL Mission

Welcome to the jOOQ Tuesdays series. In this series, we’ll publish an article on the third Tuesday every other month where we interview someone we find exciting in our industry from a jOOQ perspective. This includes people who work with SQL, Java, Open Source, and a variety of other related topics. We are excited to talk with Markus Winand in ...

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The 10 Most Popular DB Engines (SQL and NoSQL) in 2015

About two years ago, we’ve published this post about the 10 most popular DB engines, where we analyzed the data published by Solid IT on their DB Ranking website. In the meantime, the Solid IT measurement system has found to be a credible source, such that the website has also been cited at Gartner, InfoWorld, and many other sources. Comparing ...

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You Probably don’t Use SQL INTERSECT or EXCEPT Often Enough

When people talk about SQL JOIN, they often use Venn Diagrams to illustrate inclusion and exclusion of the two joined sets: While these Venn diagrams are certainly useful to understand (and remember) SQL JOIN syntax, they’re not entirely accurate, because SQL JOIN is a special type of a cartesian product, the CROSS JOIN. In a cartesian product between two sets ...

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Don’t Format Dates in SQL. Use the DATE Literal!

I’m seeing people do this all the time. They want to hammer a date or timestamp constant into their SQL query, and the only function they know is the TO_DATE() or TO_TIMESTAMP() date parsing function: SELECT TO_DATE ('20150801', 'yyyymmdd') FROM DUAL; As observed in this Stack Overflow question, for instance: TO_DATE ('20150801', 'yyyymmdd') AS DAY_20150801_TOTAL, TO_DATE ('20150802', 'yyyymmdd') AS DAY_20150802_TOTAL, ...

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Passing Arrays to a PostgreSQL PL/pgSQL Function

It can be handy to pass a collection of strings to a PL/pgSQL stored function via a PostgreSQL array. This is generally a very easy thing to accomplish, but this post demonstrates a couple of nuances to be aware of when passing an array to a PL/pgSQL function from JDBC or psql. The next code listing is for a contrived ...

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There is no Such Thing as Object-Relational Impedance Mismatch

Much of the ORM criticism of the last decade missed the point, being inaccurate. By the end of this article, we will conclude with the following: There is no significant difference between the relational (data) model and object oriented models How to come to this conclusion? Read on! How we came to believe in this fallacy Many popular bloggers and ...

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Divided we Stand: Optional

Our recent article “NULL is Not The Billion Dollar Mistake. A Counter-Rant” got us a lot of reads, controversial comments, and a 50/50 upvote / downvote ratio pretty much everywhere a blog post can be posted and voted on. This was expected. Objectively, NULL is just a “special” value that has been implemented in a variety of languages and type ...

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