Secret To Optimizing SQL Queries - Understand The SQL Execution Order

Animation tools: Adobe Illustrator and After Effects.

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[cumbi-mongo]

Great video! One addition: The "EXPLAIN" command is an invaluable tool for optimizing SQL queries. It provides a detailed execution plan, allowing the developers to understand how the database engine processes a query. By analyzing the execution plan, you can address the performance bottlenecks with proper optimizations, e.g. proper indexes.

[ayazahamed]

The way you explained with the animations are Awesome. Great Job. Very Well Explained.

[yicpuhf]

bro this way of teaching is really really make sense. thanks a lot for these visuals.

[lucyk]

Thank you for a fantastic visualization of the SQL queries execution order. That's exactly what I have been missing in the other materials. I really appreciate your style of teaching

[JohnS-erjh]

One of the best SQL videos I have come across, just the way it is put together and the infographics. If you are learning SQL, you really should understand the mechanics behind optimizing queries, how databases work. Just adding more hardware or VM resources will not fix the issue if your queries are not optimized properly.

[uzair]

Opt for indexes with SELECT, WHERE, JOIN clauses.
Use full column comparison to get data instead of half or computed comparison (i.e startsWith)
Avoid ORDER_BY on large data retreval
Use limit of smaller number with pagination for more data.

[siuedvy]

This is the best explanation I've ever seen. Big thumbs for you!

[AliBensoukehal]

Simple and to the point explanation. Love it. Thanks 👍

[abhinavx]

Very profound, please share more on SQL like windows and CTE, your explanation is very approachable.

[bonita]

What a Video, Voice, Explanation , Graphics and etc...well done mate

[karunakaranr]

Thank you for your time and effort to explain any of the subjects. Really like it and more over able to register the concept in mind easily. Thanks again, .

[iturbcn]

Additionally, for the optimizer to "make up" a reasonably good plan (from the various alternatives), it needs to know a bit about the data (value) distribution. This is where STATISTICS / ANALYZE (depends on the DB vendor) come handy. It helps the optimizer do estimates for the various steps (rows, size of data, etc.) of each plan, and figure out which of the different plans is the best candidate to execute. Therefore it is important to collect this information on critical columns (usually join, where clause columns). It is also important to keep this information regularly refreshed so that the optimizer does not make bad decisions based on stale statistics. Very bad things can happen with stale statistics.

[CyberMew]

Very good intro. Would like a more detailed explanation on more complex queries.

[caseyspaulding]

Wow. To the point with knowledge I can use today. Thank you.

[avijeethati]

Excellent video explaining basic concepts in very short time..❤

Impressive graphic animation, could you please share how the execution plan animation was done

[MrSuriyam]

Hi Sir thank you 🙏 for taking the time to explain the SQL. Sorry Iam new and very helpful.

[JeremyChone]

wow, what an awesome introduction to SQL optimization.

[stpaquet]

Understanding how the DB engine works with indexes is key. you may assume that a WHERE purchase_date >= 2022 AND purchase > 100 would be the same if you have indexes on purchase_date and purchase, but it might be required to have a composite index... Order in the WHERE clause may also be important as it helps reducing the dataset before applying the second condition.

[moneycrab]

I heard it called "predicate pushdown" when you move a condition earlier in the plan

[yqsison]

Awesome visualization, I've been loving all the short videos on this channel!

Clarifying Q. The execution order has SELECT happening after HAVING, so this should mean that the calculated column total_spent doesn't exist at the time the HAVING clause is evaluated?