Views — Reusable Query Logic
title: “Views (Virtual Tables)” part: 3 topic_number: 3 slug: “views” difficulty: “Advanced” prerequisites: “multiple-joins, aggregate-functions” — Views — Reusable Query Logic What Is It? A vie...
Rahul Chandna
Date and Time Functions — Working with Temporal Data
title: “Date and Time Functions” part: 3 topic_number: 2 slug: “date-functions” difficulty: “Advanced” prerequisites: “aggregate-functions” — Date and Time Functions — Working with Temporal Data ...
Multiple Joins — Combining 3+ Tables
title: “Multiple Joins (3+ Tables)” part: 2 topic_number: 4 slug: “multiple-joins” difficulty: “Intermediate” prerequisites: “inner-join, left-join” — Multiple Joins — Combining 3+ Tables What Is...
Self Joins — Comparing Rows Within the Same Table
title: “Self Joins” part: 2 topic_number: 3 slug: “self-joins” difficulty: “Intermediate” prerequisites: “inner-join, left-join” — Self Joins — Comparing Rows Within the Same Table What Is It? A...
CASE WHEN — Conditional Logic in SQL
title: “CASE WHEN (Conditional Logic)” part: 2 topic_number: 2 slug: “case-when” difficulty: “Intermediate” prerequisites: “select-from-where” — CASE WHEN — Conditional Logic in SQL What Is It? ...
SUBSTRING — Extract Parts of Text
title: “SUBSTRING” part: 2 topic_number: 1 slug: “substring” difficulty: “Intermediate” prerequisites: “string-functions-upper-lower” — SUBSTRING — Extract Parts of Text What Is It? SUBSTRING() ...
String Functions (UPPER, LOWER)
title: “String Functions (UPPER, LOWER)” part: 1 topic_number: 20 slug: “string-functions-upper-lower” difficulty: “Beginner” prerequisites: “select-from-where” — String Functions (UPPER, LOWER) ...
NULL Handling
title: “NULL Handling (IS NULL / IS NOT NULL)” part: 1 topic_number: 19 slug: “null-handling” difficulty: “Beginner” prerequisites: “select-from-where” — NULL Handling What Is It? NULL represent...
DISTINCT
title: “DISTINCT” part: 1 topic_number: 18 slug: “distinct” difficulty: “Beginner” prerequisites: “select-from-where” — DISTINCT What Is It? DISTINCT eliminates duplicate rows from your query re...
LEFT JOIN
title: “LEFT JOIN” part: 1 topic_number: 16 slug: “left-join” difficulty: “Beginner” prerequisites: “inner-join” — LEFT JOIN What Is It? LEFT JOIN returns ALL rows from the left table, and match...