Filtering: Intermediate

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Boolean logic: it's complicated

Category

SQL

Difficulty

intermediate

Duration

24 minutes

Challenges

0 hands-on challenges

Topics covered: OR and CASE expressions, Operator precedence, LIKE for pattern matching, LIMIT and OFFSET for pagination, BETWEEN for range filtering

Lesson Sections

1. OR and CASE expressions (concepts: sqlCaseWhen)

   OR: Branching in WHERE CASE WHEN in SELECT How They Compare Which approach labels users as admin vs non-admin?

2. Operator precedence (concepts: sqlOperatorPrecedence)

   SQL evaluates operators in a specific order. Knowing this order prevents logical errors in complex conditions. Default Evaluation Order Parentheses () control the order in which SQL evaluates conditions. They act as explicit grouping tools that override default logical precedence. Without parentheses, SQL follows a fixed hierarchy: When a condition involves multiple operators, parentheses ensure the database interprets your intent correctly. They determine which comparisons are grouped and how c

3. LIKE for pattern matching (concepts: sqlLike)

   When exact matching is too restrictive, pattern matching lets you find rows based on partial values. Why use LIKE? The first pattern starts with Ann, the second ends with @company.com, and the third uses underscores for unknown digits. Wildcard Patterns Suffix Matching This filter keeps any email ending with @orbit.ai regardless of the username. The database scans the email column row by row and keeps entries whose suffix matches the wildcard pattern. Which pattern finds emails ending in .com? T

4. LIMIT and OFFSET for pagination

   Why limit rows? Example Navigating Large Datasets Pagination Syntax This skips the first 10 rows and returns the next 5 (rows 11-15). Which query safely gets the top 5 spenders?

5. BETWEEN for range filtering (concepts: sqlBetween)

   What BETWEEN does It keeps range logic concise, especially when both bounds are constants or parameters. Combining Multiple Ranges Multi-Range Filtering For date range queries, always consider whether you need inclusive or exclusive boundaries because including midnight on the last day can pull in unexpected records.