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Learn SQL Once, Use It for 30 Years

https://fagnerbrack.com/learn-sql-once-use-it-for-30-years-9aceb0bdee03
> If you are a junior developer, “learn SQL properly” is the most valuable 40 hours you can spend. Not a tutorial. Not an ORM. Actual SQL: joins, subqueries, window functions, query plans. That investment pays you back at every job, in every stack, for decades

This is the power of low-level reasoning.

Today, even for a junior developers, even if they have AI that solves syntax problems, SQL teaches you to reason and approach problems logically. Without any wrapper masking low-level logic.

It's something like the letters of the alphabet that form concepts: why should they change?

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I find SQL a very thick "wrapper masking low-level logic". Think of the query planning, the index-maintaining, the upholding of guarantees, the writing-to-disk and caching that you are all not doing by using a RDBMS!

I'd say SQL is a very high level language.

"SQL teaches you to reason and approach problems logically" -- I kind of agree here. It teaches relational data mgmt. I think it is better to attack most software design challenges at a higher level, and --once settled at that level-- consider how to "serialize" those solutions to an RDBMS (if that's the tech that you've chosen for persistence; still a very solid choice after 50+ years!).

>, SQL teaches you [...] Without any wrapper masking low-level logic.

I understand the point you're trying to make, and yes, it does seem like SQL is "low-level" from the perspective a wrapper like ORMs or a GUI db browser tool with menus for filtering data.

But it's also worth remembering that SQL itself is a high-level wrapper that hides the lower-level C/C++ code of the db engine that has the loops that iterate through b-trees, 8k data pages, memory blocks of the buffer cache, etc.

And C/C++ itself is a high-level wrapper that hides the logic in lower-level Linux o/s system calls that manages RAM and disk i/o.

And Linux itself is a high-level wrapper that hides low-level device drivers like SATA/SSD memory-mapped IO ... and so on and so on.

Depending on the type of app, you can ignore all the lower levels and just work at the abstraction level of higher-level wrappers.

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A couple of sites worth checking out to level up, both by Markus Winand:

https://modern-sql.com/

https://use-the-index-luke.com/

also a few different para-sql languages that can be useful, to lower the complexity:

- https://prql-lang.org/ - https://www.malloydata.dev/

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>The Only Programming Language Built on Mathematics, Not Fashion

As a modern array language D4M is the natural successor for SQL [1].

D4M is based on mathematics like SQL, specifically associative array algebra but not relational unlike SQL. It's more generic since can it caters to most modern data abstractions including spreadsheets, database tables, matrices, and graphs [2].

You can achieve 100M database inserts per second with D4M and Accumulo more than a decade ago back in 2014 [3].

[1] D4M: Dynamic Distributed Dimensional Data Model:

https://d4m.mit.edu/

[2] Mathematics of Big Data: Spreadsheets, Databases, Matrices, and Graphs:

https://direct.mit.edu/books/monograph/5691/Mathematics-of-B...

[3] Achieving 100M database inserts per second using Apache Accumulo and D4M (2017 - 46 comments):

https://news.ycombinator.com/item?id=13465141

There is no SQL successor: SQL is here to stay.

Applying the Lindy effect [1]: after half a century of SQL we can expect it to survive for at least as long.

Disruption/displacement of SQL is like attempting to replace email. It's not going to happen. At best an alternative technology can carve out a small niche (and there's nothing wrong with that).

[1]: https://en.wikipedia.org/wiki/Lindy_effect

That wikipedia article was super interesting, I'd never heard of the Lindy Effect before. A bit difficult to wrap my noggin around but really fascinating to think about.
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The power of SQL is not because it is "based on mathematics" - it's because anyone (really, anyone, even with the most basic English skills) could understand it quickly enough to start using it productively with not much technical knowledge. Business analytics, managers of all sorts, manual QA people could grasp the basics in a minute and more complex queries within a few hours. It is very user-friendly and such tools win over anything else. Each time I see an overengineerd/overcomplicated solution that is hard to read/understand - I know it's only "good luck" to the creators.
The only one? As opposed to ... Haskell, LISP/Scheme in the original SICP version, and proof assistant languages like Lean.
Sounds interesting, but how can I use it to talk with an Oracle/MySQL/PostgreSQL database?
I feel you missed the point of the article :)
I feel like the point of the article was "hey chatgpt write me an article about SQL"
I’d say the most impactful thing is not to learn SQL, but set theory.

Well-written SQL is about thinking in sets. I cannot tell you how many poorly written procedural stored procedures I’ve replaced with a single performant SQL query over the years.

This is because the most impressive part of the SQL ecosystem is the DBMS engine’s query plan. Though, yes, you have to know how to influence it.

I find ORMs also tend to keep devs thinking procedurally.

Yes learn SQL! But don’t just learn the syntax. Learn the underlying mathematical models and ways of thinking that SQL supports implementing.

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But you cannot learn it “once”. You need to continuously use it (over those 30 years, for example) to be proficient at it. It’s not that you can study sql for let’s say, 30 days, and never touch/study it again.

I did “learn” sql at uni… but had to study it again at every company i worked for (different problems triggered different solutions). Im still learning it.

- I recently read that most programmers SQL knowledge is outdated by 20 years and it’s true for me. There are quite a lot of features in most DBs that feel very "new" to me.

- Comparing SQL to React weakens the argument. SQL is the language, React is a piece of software. You certainly can run 30 year old JS today in modern browsers.

I think the pretext of this articles is ridiculous.

Yes, SQL is based around relational algebra, but all programming languages are built on a theoretical foundation.

And SQL is very much a "fad" language - it just somehow managed to stick around. The goal was not some sort of mathematical purity, but rather to built a natural language data interface (sounds like something currently very hyped?) and it failed spectacularly at that goal.

It is so far from natural language that English speakers with statistical understanding won't be able to read it, but it is also inconsistent enough in its grammar design that it is unreasonably difficult to learn and needs large refactoring every time you want to query into the result of a query.

To continue my rant: Sometimes '=' is an identity test, sometimes it is `==`. Sometimes groups are called groups, sometimes they are partitions.

When creating a CTE, you put the name before "AS", but when creating a column, you put the name after "AS".

SQL is great because it is everywhere and it is definitely good enough, but it is not something great, that transcends other programming languages.

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I found PRQL[1] to be good fix for nearly everything I dont like about SQL.

But then it's only a query lang (DDL you still do in SQL then I guess).

Bottom line for me now is that I dont write much of my SQL by hand. AI does a much better job at it. I just read it back and point out mistakes and/or inefficiencies.

1: https://prql-lang.org/

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I've been slowly transitioning from using an ORM to just plain SQL. It's so much simpler. Less magic, more explicitness, and more control. Also, much better performance. I think the thing is to construct your model around the different queries you need to perform. In many cases, especially a CRUD-type situation, you'll end up with 10-20 different SQL queries, and that's it.
Once you break free of ORM’s I find the code so much simpler to maintain.

Here’s the query(typically multiple different subqueries and return types), here’s the params, give me all the data back and something like Dapper in .net is an absolute godsend to convert it.

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That's true. SQL knowledge is one of the few skills that didn't age.

1. C language.

2. *nix tools (shell and friends).

3. SQL.

4. Basic IPv4 networking.

These things I learned around 20 years ago, they didn't change much and they are useful for me to this day.

I was a fan of Seven Languages in Seven Weeks [1] because it exposed you to different paradigms which you could then try to apply where they made sense on whatever tools you were using or building: prototype based, fault tolerante, funcional, logical. Very fun book when used right.

The point being that sometimes the tools themselves don't need to survive because you take the lessons from one thing to another (e.g. move semantics and rust/modern c++)

[1] - https://pragprog.com/titles/btlang/seven-languages-in-seven-...

The comparison with JavaScript as an exemplary imperative language is silly. You can find examples of C code from 40 years ago that still work perfectly with modern compilers. Like C, SQL is a technology that has far outlived its usefulness, though, for very different reasons. SQL was not designed for application development, and every attempt to integrate it into higher level programs (ORM, fluent query builders, raw strings, macros/preprocessors) comes with unpleasant rough edges. The best thing young developers can do is read a book like "Designing Data-intensive Applications" and learn how the fundamental technology behind databases work. Learning relational modelling is great, but learning SQL itself, unless you actively have to work with it, is a waste of time.
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> Edgar Codd formalised relational algebra in 1970. SQL sits on top of it as a declarative interface. You describe what you want. The database engine decides how to get it. The engine improves every year. Your query stays the same.

Although SQL is of course not relational Algebra (and others like Datalog and D4M are better), it's still cool. It inspired kSQL like Lil uses https://beyondloom.com/decker/lil.html#lilthequerylanguage , which inspired the code I'm most proud of: https://codeberg.org/veqq/declarative-dsls A common query language, a common idiom, for many data structures (arrays, hashmaps, datafremas) is liberating, permitting you to e.g. solve sudoku, make mandelbrot sets or calculate primes directly:

    (def n 40) # to reach primes up to, left is sqr of n, right n/2, then multiply them for rows
    (def composites
    (df/select :from (range 2 (+ 1 (math/floor (math/sqrt n))))
               :cross (range 2 (+ 1 (/ n 2)))
               :where |(<= (* ($ :value_left) ($ :value_right)) n)
               [[:value_left :value_right] :value
                |(* ($ :value_left) ($ :value_right))]))
    (df/select :from (range 2 (+ 1 n)) :exclude composites)
Or e.g.

    (import declarative-dsls/dataframes :as df)
    (def people (df/dataframe :name :age :job))
    (df/dataframe? people)
    
    (df/insert! {:name "Bob" :age 30 :job "Developer"} :into people)
    (df/insert! {:name "Alice" :age 27 :job "Sales"} :into people)
    (df/update! :set {:job "Engineer"}
             :where |(= ($ :job) "Developer")
             :from people)
    
    (df/save-csv people "people.csv" :sep "\\t")
    (def people2 (df/load-csv "people.csv" :sep "\\t"))
    
    (-> people2
       df/dataframe->rows
       df/rows->dataframe
       df/print-as-table)
The tests file has many such things (like the sudoku solver) and even datalog and minikanren implemented on top of this!
Datalog is the dream. But SQL with a good query builder like Clojure's honeysql is not so bad.

That and SQLite seems to be able to scale to almost any problem, is disgustingly fast and with litestream incredibly resilient.

My first job in 1994 was using RDB, very soon updated to RDB-Oracle 6 that was very compliant with my book about sql 92. I learned SQL during my studies, so my queries based on joins naturally performed well, unlike the nested SELECT statements in the legacy code. I learned to tune performances. After that, I've encountered Oracle with its share of non-standard syntax and behavior. Now, when I build a backend (flask or fastapi), my CLAUDE.md contains "use sqlite without sqlalchemy" so that I can understand how data is accessed and check that there is no hidden query inside a loop. When the SQL queries generated by AI become unreadable, it’s a sign that the system is no longer functioning properly. In my view, SQL is a good way to maintain control over an application that is largely generated by AI.
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> The Only Programming Language Built on Mathematics, Not Fashion

Had to reread the title again since I thought I opened a different article about TLA+.

As for SQL, if you're referring to DBMS systems, here's what E.F. Codd, inventor of relational algebra, had to say about them and the departure from his work: https://thaumatorium.com/articles/the-papers-of-ef-the-coddf...

I’ve always felt that SQL is somewhat easy to grasp for basic queries, but gets complex and difficult for even moderate to higher complexity use cases. My eyes glaze over when I read long stored procedures that someone else has written. Any recommended resources to go from beginner/beginner-intermediate to advanced?
I think advanced SQL authoring is generally simple to understand, and that's the larger learning curve!

I find those big stored procedures usually fall into two categories; logic that should be in the DB, but should be decomposed (staging tables, other SPs, etc) in which case they can be understandable in chunks; or logic that shouldn't be in the DB but has been shoved in there, in which case there's more of an ideological debate but I generally prefer to pull out and run in the application layer. (the latter is pretty much IMO the things that you've done after you've gotten the data at the right grain, when you are massaging it to a particular form/presentation format; performance is often the final arbitre here though).

My advice is: don't write complicated SQL.

The best thing I learned about SQL is that it can do an awful lot of clever stuff but that the vast majority of the time you really don't need it. Learn the basics. Shrug the rest off.

The way to learn advanced SQL is to challenge yourself to find a set oriented solution and avoid procedural code. The more unreasonable it feels, the more you learn.

If the solution you find is longer and not much faster than the procedural alternative, you throw it away and fall back on procedural code.

Stored procedures are not advanced SQL. Most of them are not SQL at all. There are a few legitimate reasons for using SPs such as reducing roundtrips to the database and writing little pure functions for use in SQL statements.

But many uses of SPs are just laziness or a symptom of organisational dysfunction.

I feel like stored procedures and co crosses over into the realm of application programming, and while I can't speak from experience (so take this with a huuuuge grain of salt), this is where things break down. It feels like adding logic / basic programming to JSON/YAML, which are data/config languages primarily.

I think stored procedures - or anything that goes beyond storing / looking up data - had a place when a database had multiple different clients, but with modern day systems that's less likely to be an issue.

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I've learned SQL around 20 years ago, and in all this time I've felt it was just a poorly designed language. It was always infuriating to write because of its verbose nature. Keywords were split into two words. I'm still shocked it's not "GROUPBY". There is no composition and modularization of logic, queries become massive expressions.

I know I'm in the minority in places like this, but I've spent all my life using ORMs, and never once regretted it. And I'm the kind of person that actually likes low-level C from time to time. SQL just feels like a poor abstraction layer: either go higher or lower.

It’s a good abstraction layer, and a fundamentally good/effecient model of organization and data management. It’s a horrible language, has a meaningless standards doc, some of the worst debugging tooling of modern system and generally any tooling outside of the RDBMS engine itself is 20 years stale.

The only difficult part in arguing this is that RDBMS != SQL != RelationalAlgebra, and it’s very often forgotten

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Well-designed purpose-built tools stand the test of time. When you need a hammer you need a hammer. I learned to swing a hammer a very long time ago, and that skill has stayed with me on modern-day hammers - I didn't have to learn the New Way Of Hammering Things.
I’ve been using Postgres for over 6 years (since I started), and I honestly think it’s one of the best investments you can make as a developer
Alternatives come and go, SQL stays.

It's not that I like or dislike SQL, it is just that it has such raw power and mature tooling/resources, I wonder what an alternative could even offer me.

It's like C. It does such a great job at being structured assembly that it is hard to displace it for similar reasons.

the main reason i dont like sql is the way it splits your query into parts that run in a different order and you can only have one of each. thats why you need things like ctes. if it was a more "functional" language with features like let bindings it would be easier to understand (and maybe to optimize):

  from customers as c
  let orders := all(orders where customer_id = c.id)
  select c.name, count(orders), avg(orders.price)
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One of the best things that happened to me is my boss giving me a crash course in advanced SQL at my first job. In the database we used at work, he gave me increasingly difficult questions to answer with queries.

It was a great foundation and has served me well to this day.

Additionally learn stored procedures.

Helps simplify complex SQL queries and no need to waste network traffic on data that client side is never going to use, and waste CPU cycles processing it.

Yes, what about database portability?

I am on my 50s and it only mattered on a single project, which was anyway a middleware for application servers.

> Additionally learn stored procedures.

For sure, but have a solid grounding in set theory to go with it.

I've dealt with so many poorly-performing stored procedures that ended up being written as iteration over a CURSOR when they could have been done with sets. Programmers who don't grok set theory reach for iterative constructs which, while they work fine, are an impedance mismatch with SQL.

At least in that case you can refactor the stored proc to be more performant without pushing application changes.
Agreed, however that applies to SQL in general.

I have seen DBAs make wonders without changing queries, only by adding the right set of indexes.

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This is standard advise I give to any IT consultants (incl some that didn't ask for any lol). Cos I see too many of them evolving into purchasing clerks and postmen, far removed from the tech and operations.

Regex, SQL, Basic linux command line tools, awk. More as job demands.

For me SQL has long been the gateway to the world of development. I work in the UK non-profit sector and traditionally this kind of technical knowledge is rare, so for any team I've worked with I've built learning pathways that start with SQL before pushing out into Python, Linux, and other things. We're not exactly at the bleeding edge of current technologies, but SQL has consistently proved to be a great jumping-off point for novices who have even a passing interest in computing.
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I fully agree with the title (with reservation for "dialects"), and I believe the same can be said for JSON and Markdown, among possibly others.
Same can be said for learning an OO programming language or a procedural programming language. I learned C++ at school and started using Java on my first job. I forgot how to work correctly with pointers but I have tried multiple languages (using the same paradigms) and managed to build working software
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I've played once with codesignal to pass SQL chapters and it really helped to advance querying skills.
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Just, for god's sake, move SELECT after GROUP BY, I beg you.
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Agreed. SQL has been one of the most stable and useful skills I have.

Rivalled only by Linux, shell scripts, and Cron!

I resisted learning SQL for years. When I finally got around to learning it, I kicked myself for not learning it sooner. Sure, it has its share of jank and every DB has its own flavor, but at the end of the day you can do insane amounts of data processing using an easy to learn, although sometimes difficult to master, query language.
Learn Cobol once, use it for 100 years :-D
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> Now try this experiment with the JavaScript ecosystem. Take a React component from 2015. React.createClass, mixins, componentWillMount. It doesn't just look old, it throws TypeError: React.createClass is not a function the moment it loads. You rewrite it from scratch to ship it today. Ten years passed, and the framework cycled through three different mental models in that time.

Pretty absurd comparison. SQL is a language, React is not. SQL has been around for over 30 years, React has not.

This is what I refer to as React Derangement Syndrome.

> JavaScript is an imperative language that browser wars, framework trends, and open-source maintainer preferences reshaped every few years. It rewards you for keeping up.

> SQL rewards you for sitting still.

Again, this is apples and oranges. These technologies are in far different places in their history. JavaScript that worked 20 years ago still works today.

You can write an article about how great SQL is without having to bring React up. I promise it's possible.

I don’t think it’s rational to flatten data. If an item contains an array of sub items which in turn contains an array of subitems, that item belongs in one place not three tables.

I know those view isn’t popular, but I’ve happily used Linux, Python, virtualisation, node and Rust when they were laughed at and I’m not particularly concerned.

Having been working with computers professionally for almost 40 years now I've seen quite a lot of things come and go. I'm not convinced that LLMs will stick around for that long although they're currently doing better than "fuzzy logic", which is what it used to be called when they could run on 68HC11s ;-)

You know what has stuck around though?

Thumping great Unix boxes running SQL databases.

Yes, there's a lot wrong with the whole concept, but everything else is in some important way worse.

was this article secretly written by regexp
> JavaScript is an imperative language that browser wars, framework trends, and open-source maintainer preferences reshaped every few years. It rewards you for keeping up. > Take a React component from 2015

Javascript is actually fully backwards-compatible, to not break the Web. Any javascript from 10 years ago works in the browser. This is good but also a bit of a burden, since the language can only expand but not shrink. React is a library, and like all libraries it has breaking versions. Not understanding the basic difference between the two kinda undermines the credibility of the article.

Also, in a similar way, core, ANSI SQL is largely backwards compatible, but all the SQL dialects linked to various DBMS implementation are generally incompatible. Obviously that's not mentioned in the article.

> Not a tutorial. Not an ORM. Actual SQL: joins, subqueries, window functions, query plans.

Not text written by a human. Not a style that an real writer would ever use. Actual AI slop: Short sentences. Incorrect facts. Not X, Y.

> Not a tutorial. Not an ORM. Actual SQL: joins, subqueries, window functions, query plans.

My brain absolutely checks out when I read this stuff now.

Not to mention that query plans are absolutely not "actual SQL".

An article laser-targeted at HN's front page, making tantalizingly negative and easily disprovable claims about Javascript? Perish the thought.
> SQL is the only programming language

SQL is not a programming language. You do not write programs in SQL. It's a declarative language (or set-of-sublanguages).

> a working developer can learn once and > use for 30 years without rewriting their mental model.

There is any number of long-living languages which satisfy this.

Plus, SQL it's not even really a single language, because the spec changes, and is huge, and few people know it fully; and the dialects have non-trivial differences; and if you switch DBMSes, you often switch SQL dialect. In that sense, it is very much like other programming languages which evolve, like C++ or Fortran or even C.

It's broken expression to update karma brings downvotes

  UPDATE users
  SET karma = 9001
  WHERE name='notlibrary';
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Everyone knows SQL already. The harder parts that pay off are schema design, knowing how to interact with your DB in code, and knowing all the ins and outs of whatever DBMS you're using.
I would emphasize the importance of batching and set operations. This is where I think many developers lose track of the rabbit, because you don't have much control over either of these things via ORMs. You have to get your hands dirty with raw command text.

The value of this stuff is difficult to overstate. Batching allows for you to rapidly load the RDBMS. The first few times you test, it will probably go so fast you won't believe it loaded anything at all. Set operations allow for you to bring this newly loaded data to visibility in production tables nearly instantly. Your OLAP & OLTP workloads should be dominating the compute. ETL ops (loading/set ops) should be a ghost in terms of cpu time and memory. None of this is vendor specific knowledge. Every major engine has a reasonable way to bulk load and perform quick merging of records.

> I would emphasize the importance of batching and set operations.

Please, preach your gospel more loudly and frequently. It always feels like people complain about RDBMSs being slow because they run insert queries one at a time.

Well yeah they should've banned ORMs in the Geneva Convention. Quickest way to irreversibly ruin your schema design and backend code.
I refuse to learn SQL. I'm not a computer, I'll let them deal with that.
SELECT excuse FROM ignorance ORDER BY snobbery DESC LIMIT 1;
Love it! I am speaking as someone who has used SQL for over two decades with very good success. I find it extremely logical and a good fit for my mental model. Long live SQL!!