SQL Wildcard Characters: LIKE Patterns, ESCAPE Rules, and Examples | DbSchema
Learn SQL wildcard characters with %, _, ESCAPE, ILIKE, and NOT LIKE examples. Compare databases and test safe pattern searches in DbSchema.
Tutorials
Every post tagged tutorials on the DbSchema blog.
SQL NULL Functions Explained with Examples | DbSchema
Learn SQL NULL-handling functions like IFNULL, ISNULL, COALESCE, and NVL, with examples, pitfalls, and practice exercises.
SQL HAVING Clause: GROUP BY Filters, Examples, and HAVING vs WHERE | DbSchema
Learn SQL HAVING with GROUP BY using COUNT, SUM, AVG, JOIN, and COUNT DISTINCT examples. Understand HAVING vs WHERE and write safer reporting queries.
SQL ANY and ALL Operators Explained with Examples | DbSchema
ANY is true when one subquery row matches, ALL only when every row does. See each operator form, IN and EXISTS, and what NULLs and an empty subquery do.
SQL SELECT INTO Statement Explained with Examples | DbSchema
SELECT INTO copies a query result into a new table. Syntax, examples with their results, what the copy keeps, and what to use on MySQL, Oracle and SQLite.
SQL DELETE Statement Explained with Examples (2026) | DbSchema
Learn SQL DELETE syntax with WHERE, JOIN, and subquery examples plus transaction-safe cleanup patterns. Includes DELETE vs TRUNCATE vs DROP and production safety tips.
SQL UPDATE Statement: Syntax, Examples, and Safe Patterns (2026) | DbSchema
Learn SQL UPDATE syntax with practical examples, WHERE safety checks, JOIN-based updates, and transaction-safe patterns for MySQL, PostgreSQL, and SQL Server.
SQL MIN() and MAX() Functions Explained with Examples | DbSchema
SQL MIN() and MAX() explained: syntax, NULL handling, GROUP BY and ORDER BY, WHERE vs HAVING, text and date columns, and selecting the full row.
SQL Tables Explained: CREATE, ALTER, DROP, and Examples | DbSchema
Learn SQL tables with practical examples: what a table is, how to CREATE, ALTER, and DROP tables, and how primary keys and constraints work.
SQL ORDER BY: Syntax, ASC/DESC, Multiple Columns, and Pagination | DbSchema
Learn SQL ORDER BY with examples: ASC/DESC sorting, multiple columns, NULL handling, LIMIT/OFFSET pagination, CASE expressions, and performance tips.
SQL NULL Values: IS NULL, COALESCE, NULLIF, and Common Pitfalls | DbSchema
Learn how SQL NULL values affect filters, joins, aggregates, UNIQUE rules, and NOT IN queries. Use DbSchema to inspect nullable columns and test fixes safely.
SQL INSERT INTO SELECT: Syntax, Examples, and Safe Data Copy | DbSchema
Learn SQL INSERT INTO SELECT with JOINs, filters, duplicate prevention, and transaction-safe data copy patterns for MySQL, PostgreSQL, and SQL Server.
SQL Joins Explained: INNER, LEFT, RIGHT, and FULL JOIN Diagrams | DbSchema
Learn SQL JOINs with clear INNER, LEFT, RIGHT, FULL, CROSS, and SELF JOIN diagrams, examples, and FAQs. Build and test joins visually in DbSchema.
SQL COUNT, AVG, and SUM with GROUP BY: Syntax and Examples | DbSchema
COUNT(*) counts every row including NULLs, COUNT(column) skips them, and SUM and AVG ignore NULL. SQL COUNT, AVG, SUM syntax with GROUP BY and HAVING.
What Is a Foreign Key in SQL? Syntax, Rules, and Examples (2026) | DbSchema
Learn SQL foreign key syntax with examples, ON DELETE and ON UPDATE actions, composite keys, and how to add or drop constraints in MySQL, PostgreSQL, and SQL Server.
What Is a Primary Key in SQL? Definition and Examples (2026) | DbSchema
Learn what a primary key in SQL is, with syntax and examples for MySQL, PostgreSQL, and SQL Server, plus composite keys and primary key vs unique vs foreign key.
SQL TOP, LIMIT, FETCH FIRST, and ROWNUM Explained | DbSchema
SQL TOP, LIMIT, FETCH FIRST n ROWS ONLY and ROWNUM compared engine by engine: syntax, worked examples and the pagination form for each.
Antijoins, semijoins, and some generalized quantifiers in SQL | DbSchema
Learn about a common SQL pattern used to find rows in one table that have no matching rows in another. And some related counting problems.
SQL INTERSECT Operator: Compare Common Rows Across Queries | DbSchema
Learn SQL INTERSECT with examples, INTERSECT vs INNER JOIN, support notes, and FAQs. Find common rows faster and validate results in DbSchema.
SQL EXISTS Operator Explained with Practical Examples | DbSchema
Learn how SQL EXISTS and NOT EXISTS work with subqueries, real examples, common mistakes, and practical query patterns.
SQL CASE Expression Explained with Practical Examples
What the SQL CASE expression is, simple vs searched syntax, and examples in SELECT, ORDER BY, GROUP BY, UPDATE, INSERT, DELETE, and aggregate queries.
SQL Aggregate Functions: COUNT, SUM, AVG, MIN, MAX, and GROUP BY | DbSchema
Learn SQL aggregate functions with COUNT, SUM, AVG, MIN, MAX, GROUP BY, HAVING, and ROLLUP examples. Build reporting queries faster in DbSchema.
SQL Tutorial for Beginners with Real Examples | DbSchema
Learn SQL basics and database fundamentals with real-world examples, core concepts, and practical next steps.
SQL IN Operator Explained with Practical Examples | DbSchema
Learn how SQL IN and NOT IN work with practical examples, subqueries, common mistakes, and safe filtering patterns.
SQL LIKE Operator: Wildcards, ESCAPE, ILIKE, and Examples | DbSchema
Master the SQL LIKE operator with wildcards, NOT LIKE, ESCAPE, ILIKE, examples, and performance tips. Build pattern searches visually in DbSchema.
SQL INSERT INTO Statement Explained with Examples | DbSchema
Learn SQL INSERT INTO syntax with single-row, multi-row, default values, and INSERT...SELECT examples, plus common mistakes.
SQL UNION Operator: UNION vs UNION ALL with Examples | DbSchema
Learn SQL UNION and UNION ALL with syntax, duplicate rules, ORDER BY tips, comparisons, and FAQs. Build combined result queries faster in DbSchema.
SQL Syntax Explained with Core Commands and Examples
How SQL statements are structured, a runnable example per command family, where engine syntax differs, and how to read a syntax error.
SQL SELECT Statement: Syntax, Examples, and Query Order | DbSchema
Learn the SQL SELECT statement with syntax, WHERE, DISTINCT, JOINs, GROUP BY, ORDER BY, subqueries, and FAQs. Build queries visually in DbSchema.
SQL AND, OR, NOT Operators Explained with Examples | DbSchema
SQL AND, OR and NOT explained with runnable examples: what each returns, why precedence breaks AND/OR combinations, and how NOT behaves against NULL.
SQL Aliases Explained with Examples | DbSchema
SQL aliases explained: rename columns and tables with AS, quote aliases with spaces or reserved words, and see where an alias may be referenced in WHERE, GROUP BY, HAVING and ORDER BY.
SQL GROUP BY Statement Explained with Examples | DbSchema
Learn SQL GROUP BY with single and multi-column examples, HAVING, JOINs, aggregations, and common mistakes.
SQL SELECT DISTINCT Statement Explained with Examples | DbSchema
Learn SQL SELECT DISTINCT with single and multi-column examples, NULL behavior, DISTINCT vs GROUP BY, and common mistakes.
SQL GROUP BY Explained with Examples | DbSchema
Learn SQL GROUP BY with clear examples for COUNT, SUM, AVG, HAVING, and JOIN-based reporting queries.
SQL BETWEEN Operator Explained with Range Examples | DbSchema
Learn SQL BETWEEN and NOT BETWEEN with numeric, date, text, and time examples, plus common mistakes and best practices.
How to Create Custom Data Types in DbSchema
Create custom data types in DbSchema’s Logical Design to standardize columns; on deployment they convert to native DBMS types like VARCHAR.
SQL WHERE Clause Explained with Operators and Examples | DbSchema
Learn how to use the SQL WHERE clause with comparison, range, pattern, and list operators, plus common mistakes and FAQs.