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CS-315 route
Unit 5 · Lesson 4 of 5 13 min

Subqueries and Views

A query inside a query answers questions in two steps; a view saves a query and lets people use it like a table.

What this unit covers

Unit 5: Structured Query Language (SQL)

  1. 1 SQL Data Definition Language (DDL)Before a single row goes in, tell the database exactly what a valid row looks like. · 12 min
  2. 2 SQL Data Manipulation: INSERT, UPDATE, DELETE and SELECTPut rows in, change them, take them out, and ask for exactly the ones you want. · 13 min
  3. 3 SQL Joins, Aggregate Functions and GroupingStitch tables back together, then count, total and average whole groups of rows at once. · 14 min
  4. 4 Subqueries and ViewsA query inside a query answers questions in two steps; a view saves a query and lets people use it like a table. · 13 min
  5. 5 Query Processing and OptimisationThe same question can be answered in a second or in an hour; the optimiser's whole job is to pick the second. · 13 min