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Comment by MarkusWinand | Hacker News Reader

This is something we have to blame the vendors for.

There is an international SQL standard from ISO, it's just not commonly followed.

However, sometimes the standard isn't very useful in itself. For this example, FETCH FIRST x ROWS ONLY is the syntax mandated by the standard. Although some databases accept this in the meanwhile, LIMIT might have been a better choice as it is supported by more databases.

https://www.slideshare.net/MarkusWinand/modern-sql/120

Edit: ps.: Please don't use w3schools.com as a SQL reference. It's utterly outdated, prefers vendor syntax over standard and is sometimes just straight wrong.

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I'll disagree with you that we have vendors to blame. Vendors are trying to give users new features and support existing applications. The way new features get added to ANSI SQL is primarily by those features being adopted by multiple vendors and then one vendor's implementation (usually Oracle's) is selected as the standard.

You also have to keep in mind that ANSI SQL is a pure relational language. It's artificial in many senses. There are essentially no details of implementation in ANSI SQL. These implementation details include everything from a modular database engine like MySQL, multiple index algorithms or clustering options like PostgreSQL, deep features like external procedural languages extensions, and so on. None of these type of features are considered by the standards body. It's entirely left up to the vendors to create them. Well, a lot of features like these end up becoming standardized precisely because they become popular ways to solve problems. Statements like BACKUP DATABASE and RESTORE DATABASE are not a consideration of standard SQL because that is considered an implementation detail. Point in time recovery and log file handling are all different.

Other features like string aggregation, JSON and XML support, etc. all began as vendor extensions before they were standardized. Yes, sometimes the standard will create a new extension that no vendor supports or only minimally supports like the new MATCH_RECOGNIZE() expression. But for the most part it's the standard that lags behind and takes cues from the vendors.

Even then, the results of standard SQL sometimes are not adopted by vendors because nobody needs the features the standards body invents. Indeed, the standards body has sometimes standardized what would later be identified as bad practices. Elements like NATURAL JOIN or KEY JOIN (I think that's in the standard) are considered bad design since they result in ambiguous column joining when you start adding multiple tables or modifying the schema.

This is basically the exact same issue as XHTML vs HTML5 and browser vendors. It's not quite as bad since there's no W3C vs WHATWG political garbage (I can't imagine how bad it'd be if ANSI and ISO didn't cooperate) but it's the same kind of thing. Vendors are in competition and want to provide features that developers need. They're not going to wait for the ISO joint technical committee to decide what to do.

There's a few areas I think ANSI SQL falls down compared to some of the vendor syntax. eg I really hate the way table joins are done in ANSI SQL. I get the logic behind the syntax but the PL/SQL syntax for table joins gives me far less mental gymnastics. In fact it is probably the only thing about PL/SQL that I actually like.

Most DBAs I know consider any comma join syntax difficult to maintain and difficult to debug because it's often difficult to tell the difference between join conditions and filter conditions. It's also very easy to mistakenly create a CROSS JOIN with comma join syntax, too.

The real pain comes when you try comparing the old vendor specific OUTER JOIN syntax for Oracle and SQL Server. I guarantee you'll love JOIN ... ON ... over comma joins.

Oracle:

   SELECT * 
   FROM T1, T2
   WHERE T1.PK1 = T2.FK1(+)

SQL Server:

   SELECT * 
   FROM T1, T2
   WHERE T1.PK1 *= T2.FK1

Note that the outer indicator goes on the opposite side. Oh, and, of course, if you flip the order of the fields around, you've got to remember to flip the (+) operator. Which of these three are identical:

   SELECT * 
   FROM T1, T2
   WHERE T1.PK1(+) = T2.FK1

   SELECT * 
   FROM T1, T2
   WHERE T2.FK1(+) = T1.PK1

   SELECT * 
   FROM T1, T2
   WHERE T2.FK1 = T1.PK1(+)

Now imagine you're joining 5 tables and want to reuse the JOIN syntax.

Yeah. Fuck that. I'll take this any day:

   SELECT * 
   FROM T1
   LEFT JOIN T2
       ON T1.PK1 = T2.FK1

I have genuinly written a lot of complex SQL for both MySQL and Oracle and honestly I do prefer Oracles syntax for joins. But I did spend several years writing PL/SQL before learning ANSI SQL so I guess it might just be a question of what you're used to?

I would just be aware that the prevailing opinion is that the ANSI syntax is considered better because it's considered clearer, more maintainable, and more functional. I was perfectly fine with comma joins until I had to interact with both SQL Server and Oracle. Then I found all kinds of hidden benefits. Like if I want to query the same set of tables, I can just copy the whole FROM clause and reuse it whole-hog. The logical separation is just nice, too. My tables know how they relate to each other. They know what type of join is being done. I don't have to tell the fields how they relate to each other. Even if I get my join conditions wrong, the relationships are correct.

Even Oracle's own documentation[0] tells you to avoid the (+) syntax:

> Oracle recommends that you use the FROM clause OUTER JOIN syntax rather than the Oracle join operator. Outer join queries that use the Oracle join operator (+) are subject to [several restrictions], which do not apply to the FROM clause OUTER JOIN syntax[.]

The doc itself lists all the issues, which is about 10 of them. None of these are opinions, either. They're actually technical limitations with (+), though they may not be ones that you encounter. The only advantage I know of for the (+) syntax is some uncommon issues with materialized view optimizations.

[0]: https://docs.oracle.com/cd/B19306_01/server.102/b14200/queri...

Maybe on what you got started on. I started with T-SQL, then PL/SQL and now back to T-SQL, so you can guess which I prefer.

Me too. Joins FTW.

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