[monkeydata]

two things 1) leading commas in SQL 2) RAISE an EXCEPTION or RETURN --no more `else` statements in code

SELECT this , that , something FROM table

takes a while to get used to

[abower]

100% this. Nothing is more aggravating than having to go through someone elses SQL mess and having to reformat with commas in front. Why you ask? First, its trivial to comment a value out for testing/debugging etc, but secondly if you don't and you are reading through a large query, it is far more difficult to scan to see what fields are included, being aliased, incorporated into calculations or functions etc. This ties to the longer code, less clever mantra noted prior in the thread. The else comment I get, but I still use it and typically set it to a code or value that will push the error further up the stream. We do a lot of system to system integration so often the else part is arising from missing setup info from the source or destination so surfacing it later can ( depends on use case of course) sometimes make it easier for end users to self fix the problem by updating one of said source or destination systems.

[mekster]

What is the point of selecting specific columns unless some include large text or blob to consume unnecessary IO?

[mperdoni]

Here's a few reasons why when you finalize a query, you select only the necessary columns (non-exhaustive list):

- Reduce uneccessary IO / resource strain, as you said

- Predictability; consuming program receives data in the same order, every time

- If the DBA adds additional columns to the table, it doesn't hose downstream consumer processes

- Easier to debug if some problem does arise.

- Clarity, if you are only using a few columns from a large table. I might just be getting old though ;)

Data should be served in the simplest, most robust manner.

It should be easily consumed by other services, with little extra effort from the programmer.

If you use Select *, you either accept the possibility of it breaking unexpectedly, or have to write logic within the consuming service to deal with that. If the problem can be eliminated by the DB/query itself, it should be.

[mekster]

I understand how clarity may provide the programmer's intention of the query but I'd rather just pick all, so that change in code below doesn't suddenly break because you didn't sync the columns to be fetched.

> - Predictability; consuming program receives data in the same order, every time

For any joined table, you can specify table name for each '*' or add an alias last to keep the column you need instead of writing it all.

Seems specifying each column name isn't in any way crtitically bad when you can't select all but a column in SQL, which is a deficiency in the language.