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LESSON 3
SQL (Core) - Queries with constraints (Pt. 2)
Prereq: None | Progress: 0%
Course Syllabus
Lesson 0 📖 What is SQL? Lesson 1 📖 SELECT queries 101 Lesson 2 📖 Queries with constraints (Pt. 1) Lesson 3 📖 Queries with constraints (Pt. 2) Lesson 4 📖 Filtering & sorting results Review 1 📖 Simple SELECT Queries Lesson 6 📖 Multi-table queries with JOINs Lesson 7 📖 OUTER JOINs Lesson 8 📖 A short note on NULLs Lesson 9 📖 Queries with expressions Lesson 10 📖 Queries with aggregates (Pt. 1) Lesson 11 📖 Queries with aggregates (Pt. 2) Lesson 12 📖 Order of execution of a Query Lesson 13 📖 Inserting rows Lesson 14 📖 Updating rows Lesson 15 📖 Deleting rows Lesson 16 📖 Creating tables Lesson 17 📖 Altering tables Lesson 18 📖 Dropping tables Lesson 19 📖 Subqueries & Nested Queries Lesson 20 📖 Set Operations Summary 🎓 Course Completion
Queries with constraints (Pt. 2)
When writing WHERE clauses with text columns, SQL supports case-insensitive string comparison and wildcard pattern matching.
| Operator | Condition | SQL Example |
|---|---|---|
| = | Exact string comparison | director = "John Lasseter" |
| != or <> | Exact string inequality comparison | director != "John Lasseter" |
| LIKE | Case-insensitive pattern matching | title LIKE "Toy Story%" |
| % | Wildcard matching zero or more characters | title LIKE "%WALL-%" |
| _ | Wildcard matching exactly one character | title LIKE "WALL-_" |
Wildcards Explained (% vs _)
The percent symbol (%) represents any sequence of characters of any length (including empty sequence). The underscore (_) represents exactly one single character.
🗄️ Schema Explorer SELECTABLE
› movies
|
🎯 Exercises Checklist:
☐ 1. Find all the Toy Story movies
☐ 2. Find all the movies directed by John Lasseter
☐ 3. Find all the movies (and director) not directed by John Lasseter
☐ 4. Find all the WALL-* movies
⚡ Practice Console
💡 Hint:
Loading hint...
🔑 Solution SQL:
SELECT * FROM movies;Data Output
No results. Run query to fetch data.