Knowledge
Fundamental text manipulations in SQL
Learn practical MySQL string functions for cleaning, extracting, and combining text.
Common Table Expressions
A powerful SQL construct for structuring queries, recursion, and sequence generation.
Logical Keys in data
Use information_schema to learn about logical/business keys and find associations in messy schemas.
Explore Database with Information Schema
Use information_schema to inspect unfamiliar databases: tables, columns, foreign keys, and indexes, with an emphasis on what the metadata can and cannot reliably tell you.
Generate SQL with Information Schema
Use MySQL information_schema to inspect table metadata and generate dynamic SQL safely.
Quick Select
QuickSelect finds the k-th smallest element (0-based) in expected linear time by repeatedly partitioning the array in-place, shrinking the search to the side that must contain the answer.
Bottom-Up Merge Sort
An iterative (non-recursive) merge sort that repeatedly merges adjacent sorted runs of size 1, 2, 4, … until the whole array is sorted.
Shell Sort
An in-place generalization of insertion sort that improves performance by comparing elements far apart using gap-based passes, achieving sub-quadratic time in practice.
Top-Down Merge Sort
A stable divide-and-conquer sort that recursively splits an array, then merges sorted halves using a single auxiliary array.
Scalability
An overview of scalability as a core non-functional requirement: what it is, what it isn’t, and the trade-offs behind common scaling techniques.