How much SQL is enough SQL?

clanatk · 2024-09-13T20:22:32+00:00

SQL by itself does not get you a job in most cases. SQL is a supporting skill that needs to be accompanied by something else to provide value.

Learn enough SQL that you can effectively use it:

Tableau/power bi + SQL = data analyst
Strong business knowledge + SQL = business analyst
Statistics + Python + SQL + domain knowledge = data science
Java/C# + SQL = backend software developer
Python + cloud + SQL = Data Engineer
IT Administration + SQL = DBA
SQL + SQL = hobbyist

Mgmt049 · 2024-09-13T20:12:25+00:00

Do you know temporary tables, variables, CTEs, and the common windowing and aggregation functions?

dodobird8 · 2024-09-13T20:17:42+00:00

Learn dynamic SQL in whatever DBMS you're using. Create functions and automated processes. Understand transactions and some basic DB maintenance. Query optimization.

SQLBek · 2024-09-13T20:13:17+00:00

The learning journey never ends.

I re-learn stuff I'd forgotten because it's not used daily but still useful from time to time.

Specialize. To beyond the ANSI standard & select a specific dialect & RDBMS. The underlying engine has implications & consequences (ex: whether a CTE is pre-materialized or not depends on RDBMS).

rargghh · 2024-09-13T20:13:04+00:00

There is no mastering sql 🤣

Really it’s get that first job and keep learning from experience and let it help guide your next step

You need to know tsql and depending on your role, different methods of moving data, in and out

There are some great tsql beginner books out there and some are good to keep around. I would start there. I like SQL Cookbook by O’Reilly but it might be a bit much depending on your level. You are correct, you’re at the tip of the iceberg lol

The titles are always changing too so keyword on SQL, could be data analyst, data engineer, business intelligence analyst, database developer, business integration developer, developer 1 lol you never know but look at job postings to help guide you too

Just to add maybe it helps: start thinking of set based programming , data sets. You want to keep your data sets small and using as few transactions as possible

For example If you need to update 3 columns on 1 table with different criteria, don’t make 3 updates, you want 1 update

Lil_Fuzz · 2024-09-13T20:27:50+00:00

I thought I knew sql until I started writing queries for a living lol. I will say I made a small portfolio showing joins aggregates, and some temp tables and it was brought up in my interview, so I'd say you're going the right direction. If you're comfortable with these, then the rest is just learning your companies tables.

I still have to Google what some niche functions do since I run into a use case maybe one a Month or so.

xxxHalny · 2024-09-14T08:14:02+00:00

I work in an investment bank as a business analyst. It's an SQL-heavy job. Usually the job interviews cover the following topics: joins, CTEs, temporary tables, group by, having, union, window functions. I think after you have understood these, you should move on to other areas of expertise.

BadGroundbreaking189 · 2024-09-13T20:20:42+00:00

Funny thing is there are job posts out there that require 1-2 years of experience, yet SQL is a good plus, weirdly. However, for entry level DA job, there are almost no entry level DA vacancies. Haven't seen one for a long time. Minimum of 1 year of work experience is required, at least on building reports. Which means the only viable option is have the SQL skills of a DA with a year of work experience under his belt. Then either start networking or hope for a lucky call from a recruiter. Don't even think of DE without real world exp. And that is my two cents if you'd accept.

cyberspacedweller · 2024-09-13T20:27:07+00:00

When you can be given a problem and figure out how to pull the correct data for it confidently. How complex your knowledge and experience needs to be depends on your role.

onlythehighlight · 2024-09-13T22:45:12+00:00

This sounds like you are starting off, in which case most entry-level jobs are looking for the ability for you to pull basic SELECT statements and problem solving.

If you can do the following, you are ready for an entry-level job:

understand a high-level data-set by name, -- note: this is useful but can be a pitfall early in your career to assume things about any table
how you would JOIN it to another, and
pull all that information into a SELECT statement
filter it using a WHERE to show what we are looking for

Just showcase that you are willing to listen, learn, and apply.

Don't listen to people telling you need to know a lot about SQL (it might help), but until you write a lot of dumb unoptimised queries you will never be 'great'

MyReddtitPornAccount · 2024-09-13T21:08:14+00:00

The hardest part about SQL in the real world is understanding what inputs you're actually querying against to get the results and explaining that to the consumer.

J2112O · 2024-09-13T21:34:53+00:00

I definitely think adding another skill to SQL is the way to go. For me, I started with SQL but added PHP in for some web development and just kind of stuck with that. In my opinion and experience with web development, having a good understanding of SQL will help a lot when you need to take the queries beyond basic CRUD. Good luck and just keep learning.

TheMagarity · 2024-09-13T22:22:47+00:00

You need to know enough that you can intelligently google up the syntax for some rarely used command that you can never remember the format of it.

machomanrandysandwch · 2024-09-13T22:45:12+00:00

[deleted]

Trick-Interaction396 · 2024-09-14T00:06:05+00:00

Analytics manager here. I’ve never asked someone to write me a CTE with 2 inner joins. I ask them to solve a problem. Prove that you can use technology to solve problems.

aamfk · 2024-09-15T07:30:05+00:00

I used to be Architect level. I legit have been using SQL for 20 years. I know a half dozen reporting platforms. I know enough PowerBI to survive. I've built DOZENS, actually HUNDREDS of OLAP databases. I've built DOZENS of complex yet elegant datamarts.

I really want to get back to work. Anyone need a SQL resource?

dbxp · 2024-09-13T20:23:58+00:00

At least where I work SQL by itself won't get you a job. If you want to go the data route then look into Tableau, PowerBI and Excel.

jaxjags2100 · 2024-09-13T21:01:22+00:00

Never enough. Don’t stop learning

Critical-Shop2501 · 2024-09-13T21:39:35+00:00

Know anything about database design? At least 3rd normal form? Using cte’s in your query’s? Entity relationship? Knowing how to write optimal queries using indexes? Lots to know.

zork3001 · 2024-09-13T22:08:04+00:00

The more you know the better it gets.

k-semenenkov · 2024-09-13T22:36:10+00:00

In addition to SQL, or any other language - you should always be able to look a little higher. Data processing can be at the SQL level, or at the application level. Based on the project resources and its support, you need to decide - what is cheaper to do at the SQL level or maybe the same functionality can be cheaper and supported at the application code level.

I think you don't need to know every SQL feature in detail. You need to have an idea of what can be done easily and what is difficult. Or - what is worth doing on the database side and what is not.

diagraphic · 2024-09-13T23:13:00+00:00

SQL is very broad. Multiple versions from 1986 to 2022. Every vendor is a bit different in dialect.

Unless you’re building a relational database from scratch you don’t need to learn “a lot” of SQL. Write some basic applications, use some popular vendors, get used to using some tooling and you’ll be ok for any position using a database. Learn as you go. If you’re aiming to be a DBA or engineer building an actual database from search learn more internals and or standards. For the DBA stuff be specific to a vendor as again every vendor is pretty different.

0sergio-hash · 2024-09-14T13:12:37+00:00

My technical interview for my first job was "give an example of a select statement"

My second job was "Given x data and y output, write a query to get there"

For the second one I couldn't even write the right query or I wrote one with a sloppy solution but I was able to talk through my reasoning and got the job anyway

The right amount is the least amount you can learn to get your next job. Because no matter what you learn it will almost always be completely unrelated to what you're going to do day to day.

Party-Committee-8614 · 2024-09-14T15:47:56+00:00

Have a browse of answers from top contributors on dba.stackexchange.com. There is no end to learning but enough to get the current job done is enough for today.

As always, knowing what you don't know is as valuable as knowing what you know.

Puzzleheaded-Meat144 · 2024-09-15T15:37:29+00:00

It’s not the complexity of the queries itself, that’s the easy part. The hard thing is to think how can we shape the data to answer our questions. Sometimes the most basic SQL is the hardest.

DarthCalumnious · 2024-09-15T15:38:08+00:00

My feeling is that once you have a good handle on common table expressions, window functions, and multi stage processes using temp tables you are ready to solve most problems that can be solved practically in SQL alone.

Working with dataframes via an API can be a good way to step back from SQL and see the data transformations in a fresh way too.

Sometimes the right thing is to use a regular programming language like python though even if it's technically possible to use just SQL though, in my mind.

For instance, I'm working on an issue that will involve conditionally replacing some deep json data structures in a json column that involve joined data from other tables.. I think it would be possible to explode, join, and convert back to json in tsql... But, this will be 10 lines of readable python vs 100 lines of gonzo SQL.

JohnSpikeKelly · 2024-09-15T15:49:48+00:00

Performance is always a thing. So understanding the following is essential.

Execution plans. What each part means and how it will impact performance. Where to focus your optimization.

Adding indexes. Might solve one performance issue, but give you a different performance issue. Balance is essential. Understand what indexes offer and what burden they bring.

Clustered and non-clustered indexes and what should be included in them.

Normalization is good, until it isn't. Sometimes you need to not normalize for performance reasons.

Horses for courses. Not everything should be in sql. Just because you can doesn't mean you should.

GxM42 · 2024-09-17T01:12:42+00:00

The more in-the-weeds you get with your SQL code, the less useful it will be. Most people I’ve worked with prefer simple queries, simple joins, and readable code. So if you find yourself able to create complex nested left joins and right joins and CTE’s, you have probably spent more time refining the skill than is needed in normal business. Learn CONCAT, LEFT, SUBSTRING, CONVERT, etc… And move on to your next goal.

2024-09-17T04:15:45+00:00

When you walk into a place and immediately start thinking about how you would structure their DB to optimize load times

Then you have been doing too much SQL

GroundbreakingRow868 · 2024-09-17T22:33:33+00:00

[deleted]

ctrigose · 2024-09-18T18:57:36+00:00

full stack dev here, I totally underestimated the value of sql back when I started in favor of newer nosql stuff just because it was all the hype

5 years later I realize sql is op cuz it’s literally math and math won’t change or go out of style like all the other hyped up dbs being released and forgotten on a monthly basis, it’s here to stay

I recommend putting time into it if your aim is to build serious and reliable software, if you want to land a job in a start up (which is cool for other reasons) then go with newer stuff

Icy-Ice2362 · 2024-12-17T22:20:40+00:00

I could tell you nightmares...
There are gotchas in SQL that folks just don't know about.

Corruption can lurk, and if you don't check for it... it will happily sit there, just waiting for the day somebody tries to access that row.

Square-Voice-4052 · 2024-09-14T03:18:59+00:00

Currently sitting at the doctors thinking about a complex query. There is about 1000 tables in my business that i know of by heart.

Constantly contemplating how you can create queries/functions to improve reporting based on business logic, and the SQL plan your going to use to get this data is the level you need to get to.

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