Recent Posts
MariaDB Tutorial / Choose Conditional Values and Aggregates with CASE
Use CASE for stock labels and conditional reports. Compare branch order, ELSE and NULL behavior, and understand why COUNT with ELSE 0 counts every non-NULL result.
MariaDB Tutorial / Group Results with GROUP BY and Filter Groups with HAVING
Create category-level COUNT and SUM reports, distinguish WHERE from HAVING, and reconcile expected groups. Review output grain, ONLY_FULL_GROUP_BY, NULL keys and joined duplicates.
MariaDB Tutorial / Summarize Rows with COUNT, SUM, AVG, MIN, and MAX
Calculate and reconcile product counts, known-value counts, stock totals, averages and price bounds. Understand empty-input results and why the order of row calculations and aggregation matters.
MariaDB Tutorial / Calculate Date Intervals, Differences, and Display Formats
Compare calendar months, day differences and complete-hour differences with fixed MariaDB examples. Format dates correctly and select full months using explicit interval boundaries.
MariaDB Tutorial / Calculate, Round, and Convert Numbers with ROUND and CAST
Use exact DECIMAL inputs with ROUND and CAST, compare expected discount and midpoint results, and inspect conversion warnings, leading-zero loss and rounding-stage choices.
MariaDB Tutorial / Join, Extract, Replace, and Measure Strings
Practice concatenation, substring extraction, replacement, trimming and string length in MariaDB. Compare NULL and empty inputs and distinguish Unicode characters from UTF-8 byte counts.
MariaDB Tutorial / Check Target Rows Before UPDATE and DELETE
Inspect and lock precise target rows, verify UPDATE and DELETE results, and roll back independent InnoDB exercises. Understand affected-row counts, connection requirements and recovery boundaries.
MariaDB Tutorial / Sort and Paginate Results with ORDER BY and LIMIT
Create deterministic top lists, compare OFFSET and keyset pagination, and control NULL placement in MariaDB. Observe tied prices and understand concurrency and large-offset limitations.
MariaDB Tutorial / Compare NULL Correctly with IS NULL and COALESCE
Distinguish NULL from empty strings and zero, filter missing notes with IS NULL, choose COALESCE fallbacks and avoid NULL-related NOT IN surprises using reproducible product queries.
MariaDB Tutorial / Filter Rows with WHERE, AND, OR, IN, BETWEEN, and LIKE
Build clear MariaDB filters using comparisons, grouped AND/OR conditions, IN lists, inclusive ranges and escaped LIKE patterns. Check expected product IDs and investigate missing or extra rows.