reading-notes

SQL

SQL  stands for Structured Query Language, it is designed to let all users regardless of skill query, mainpulate and transform data from a relational database.  Relational Databases are a collection of related tables like an excel spreadsheet.

• SELECT - Query  statement which declares what data we are looking for

• WHERE - clause in query applys to each row of data, checks specific column values to determine if it is included
  • BETWEEN, AND, NOT BETWEEN, IN, NOT IN
  • LIKE, NOT LIKE, %, - , IN, NOT IN
  • DISCTINCT, GROUP BY, ORDER BY, LIMIT, OFFSET
• SCHEMA describes structure of each table and its datatypes
  • INSERT, UPDATE, DELETE
• CREATE TABLE
  • IF NOT EXISTS
  • data types - INTEGER, BOOLEAN, FLOAT, DATE, etc.
  • constraint - PRIMARY KEY, AUTOINCREMENT, UNIQUE, etc.
• ALTER TABLE
• DROP TABLE - removes entire table
  • IF EXISTS

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