SQL Aliases (AS)
Rename columns and tables in SQL with aliases (AS): readable headers, short table names in joins, aliases with spaces, and where an alias can be used.
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1,677 articles · page 15 of 140SQL NULL Values
Understand NULL in SQL: IS NULL and IS NOT NULL, why = NULL never matches, NULL in arithmetic, COUNT and sorting, and the NULL-safe operator.
SQL LIKE Operator and Wildcards
BeginnerLesson 14 of 699 min read8 queries run on MySQL 8.4= only finds exact matches. LIKE finds patterns: names that start with "A", emails at a…
SQL IN and BETWEEN Operators
Filter SQL rows with IN and BETWEEN: lists of values, number and date ranges, NOT IN, NOT BETWEEN, the inclusive ends of BETWEEN and the NOT IN NULL…
SQL LIMIT and Pagination
Use SQL LIMIT and OFFSET to return the top N rows, paginate results and find the Nth highest salary, with MySQL examples and the pitfalls of large offsets.
SQL ORDER BY
Sort SQL results with ORDER BY: ascending and descending, multiple columns, expressions and aliases, NULL ordering and custom sort orders, in MySQL.
SQL AND, OR and NOT Operators
Combine conditions in SQL with AND, OR and NOT. Learn operator precedence, why parentheses matter, and how NULL behaves in logic, with real MySQL results.
SQL WHERE Clause
Learn the SQL WHERE clause step by step: filter rows with =, , >, =, <=, text and date conditions, and avoid common mistakes, with real MySQL output.
SQL SELECT DISTINCT
Learn SQL SELECT DISTINCT with examples: unique values from one column, distinct combinations of columns, COUNT(DISTINCT) and how DISTINCT treats NULL.
The SQL Sample Database
The free company sample database used in this SQL tutorial: employees, departments, customers, products and orders. See every table and copy the MySQL script.
SQL Data Types
MySQL data types with examples: INT, DECIMAL vs FLOAT, CHAR vs VARCHAR, TEXT, ENUM, DATE, DATETIME, TIMESTAMP, BOOLEAN and JSON, and how to choose.
SQL Syntax and Comments
Learn SQL syntax rules: statements, keywords, semicolons, case sensitivity, quotes, identifiers and comments, with MySQL examples you can run.
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