Oracle SubQueries Part - 1 by Dinesh 

Thanks for the lesson. I'd already known this topic but your clear explanation helped a lot to get understanding when to use joins and when subqueries. After that, I found it clear, what and why affects performance.

Thanks 🙏. I had asked to your institute related to power center infomatica tool . They email me they do not provide infomatica training. I saw so many sql videos on you tube . You have outstanding knowledge of oracle . God bless you sir

A SQL query is not an instruction to the database about how to retrieve the result set you want, instead, it's a description of the data you want. How to get it is up to the database. Oracle will rewrite your query into an execution plan. It will search for what it thinks is the most efficient plan based on your tables, indexes, constraints, the statistics it gathers, and even guesses it makes based on the data as it goes. In fact, it's very possible you can write this query with a join and with a subquery and it leads to the exact same execution plan and the same performance. My suggestion is to write the query so that it is easy to understand what is going on. Only if the performance is actually poor should you worry about what it's doing. Oracle is pretty smart and may well find a route to your data that is better than you thought it would be. There will be moments where a join is the ideal when dealing with large data. A table with just a few rows you can just use select and where as a subquery. It's best to know when to use each.

Your explination deserve more likes...

Excellent explanation, you made the subject so simple

Thank you for your perfect explanation. Thank you again.

thank you. clear and easy to understand explanation

thanks for the tutorial sir. its very helpful and its so easy to understand :)

Thank u soo much sir, simply awesome......

Thanku...crystal clear Tutorial..!!!

awesome explanation

Nice explanation sir thank you so much

well explained. Thanks

Great explanation

May God bless you!

Thank you very much Mr Dinesh for your brilliant tutorial videos. I live in the USA how can i order your videos on oracle? I need complete training on Oracle SQL. Your explanations are very clear.

Thank u soo much sir

Tqsm sir🙏

thank you sir

Sir at 18:05 in where clause you wrote dname = 'Accounting' , i think it should be dname like 'Accounting' ? can you explain what is the difference between two ?

if we get multiple values from sub query and we have to compare those values with ''>" operator then how we can do it ? please help

sir plz make video on inline subquery

evrything explained is gd but only your cameraman is lazy😜

Subquery can also be said for the FROM clause?

Hello sir, 'tufts_jully_2021_lnvc.csv' This is the data in the oracle . So how to convert into the jully using substr. can you help me how to solve this

u did not explained difference b/w join and subquery well..learn and come here to explain

explanation is excellent but video projection is not good