Category: SQL

Read data with SELECT … FROM ….

Filter rows with WHERE conditions.

Return unique rows/values with SELECT DISTINCT.

Sort results ascending or descending.

Change existing table structure safely with ALTER TABLE.

Remove tables permanently with DROP TABLE.

Protect data quality with PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, CHECK, and DEFAULT.

Choose appropriate types for numbers, strings, dates, and JSON/blob data.

Create and select databases for your projects.

Define tables with columns, types, and constraints.