Notes/fundamentals
1
0
Fork 0
mirror of https://github.com/robindhole/fundamentals.git synced 2025-03-15 20:20:08 +00:00
Code Issues Packages Projects Releases Wiki Activity

Adds questions.

Browse Source
This commit is contained in:
Tanmay 2022-10-06 14:59:19 +01:00
parent a408ec280a
commit 7b32d3b6cb
1 changed files with 10 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
database/notes/09-subqueries-views.md
View File

@ -13,6 +13,7 @@
- [Index Range scan](#index-range-scan)
- [Index seek](#index-seek)
- [Some guidelines for optimizing MySQL queries](#some-guidelines-for-optimizing-mysql-queries)
- [Practice questions](#practice-questions)
## Sub-queries
@ -223,4 +224,12 @@ This happens when you specify a condition in WHERE clause like searching an empl
* Avoid unnecessary columns in SELECT clause
Instead of using ‘SELECT *’, always specify columns in the SELECT clause to improve MySQL performance. Because unnecessary columns cause additional load on the database, slowing down its performance as well whole systematic process.
* Pagination
* Avoid SELECT DISTINCT
* Avoid SELECT DISTINCT
## Practice questions
* [Sub-queries - I](https://leetcode.com/problems/customers-who-never-order/)
* [Sub-queries - II](https://leetcode.com/problems/sales-person/)
* [Sub-queries - III](https://leetcode.com/problems/consecutive-available-seats/)
* [Sub-queries - IV](https://leetcode.com/problems/sales-analysis-ii/)
* [Sub-queries - V](https://leetcode.com/problems/students-with-invalid-departments/)
* [Sub-queries - VI](https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/)