PHP Course For Beginners > MY SQL with PHP

Understanding Having, Distinct & Group by

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GROUP BY and DISTINCT, on the other hand, have their own uses. In some cases, GROUP BY cannot replace DISTINCT, and DISTINCT cannot replace GROUP BY. It is up to you to optimise both of them and decide where to apply GROUP BY and DISTINCT based on your preferences and circumstances.

You may utilise aggregate functions like AVG, MAX, MIN, SUM, and COUNT with GROUP BY. DISTINCT, on the other hand, only removes duplicates. This will give you one row for each department, with the department name and the sum of all the amount values in all of the rows for that department.

DISTINCT is used to separate unique records from the rest of the table's records. Duplicate rows are removed. SELECT DISTINCT will always be the same as a GROUP BY, if not faster.

In AWS Redshift, GROUP BY is also faster than DISTINCT since GROUP BY utilises an XN HashAggregate while DISTINCT uses an XN Unique.

A group by is used to group a selected set of rows into summary rows using one or more columns or an expression. Distinct is used to find unique/distinct records, whereas a group by is used to group a selected set of rows into summary rows using one or more columns or an expression. When there is no aggregate function, group by produces the same result as distinct.

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P
Prince Bavishi
5

nice work

S
sonakshi Raj
4

Excellent

S
Shibu Kumari
5

Very Good

R
Rajiv Kumar Singh
4

It would have been better if you could have provided the resource/source_code files of the CRUD operations so that we could have cross verified our code with yours.

D
Dravinanshu Mishra
5

Excellent for Bigners.

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Awais Khan
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Thanks

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Muhammad Arif jamal
5

This course is very helpful for me

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Shital Kadam
5

Thank you, sir, for providing the best course on the internet.

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Dibyadarshini Das
4

I'm getting a fatal error insted of warning and also it's not showing the if condition statement.

Aniket saini
5

must watch course to start with.

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  2. Understanding SDLC Process
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  3. How to use LearnVern
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  4. Client Server Architecture
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  5. How to set up PHP Environment?
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  1. What is Data
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  2. What is Database
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  3. What is DBMS
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  4. SQL Queries and its types
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  5. Data Types in SQL - from 16
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  6. SQL constraints
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  7. Create, Drop & Show Database
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  8. SQL Create Table
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  9. SQL Insert & Select Statement
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  10. Operators in SQL
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  11. In & NOt in Condition
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  12. Null & Not Null Condition
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  13. Clauses in SQL
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  14. Understanding Having, Distinct & Group by
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  15. Update & Delete in SQL
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  16. Alter table command in SQL
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  17. MySQL Rename truncate Drop
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  18. Understanding Foreign key
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  19. MySQL joins
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  20. MySQL views
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  21. MySQL Function
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  22. MySQL Procedure
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  23. MySQL Trigger
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  24. Normalization
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  25. Assignment : MYSQL
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  1. Understanding PHP Program structure Comments in PHP
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  2. Comparison & Logical Operators in PHP
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  2. More examples on Loops in PHP
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  2. Assignment : Header Functions
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  2. Database Connection in PHP Part 2
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  2. Crud - Registration and DB connection Part 2
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  4. Read Operation
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  5. Update Operation Part 1
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  6. Update Operation Part 2
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  7. Log out Operation
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  2. MySQL Interview Question 2
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