SQL Data Types

SQL Data Types — A comprehensive guide to SQL data types across different database systems. The guide walks through Numeric Types, String Types, Date/Time Types, Special Types. INT/INTEGER (4 bytes), SMALLINT (2 bytes), BIGINT (8 bytes), TINYINT (1 byte, MySQL). DECIMAL(p,s) / NUMERIC for exact fixed-point math. FLOAT/REAL (4 bytes) and DOUBLE (8 bytes) for approximate floating-point. Use DECIMAL for monetary values and FLOAT for scientific calculations. CHAR(n) — fixed-length string, padded with spaces. VARCHAR(n) — variable-length string with max n. TEXT — large text (up to 65535 bytes). NVARCHAR/NCHAR for Unicode (SQL Server). Use VARCHAR for most text fields, TEXT for long content (articles, descriptions), CHAR for fixed codes like postal codes. The guide is organized into 4 sections that build on each other, each pairing a prose explanation with real SQL you can run as-is. Related guides: SQL Introduction, SELECT Statement, WHERE Clause & Operators, SQL JOINs, GROUP BY & Aggregation.