Monday - Joins

Intro

Slides on Joins

###Basic Example

  • Join main table to species table
  • Show species and scientific name side by side
  • Show distinct
  • Filter by weight > 100 g

###What joins actually do

  • Join species and plots tables

###Joins are part of the Query, not the database

  • Save query
  • Close query
  • Open new query - shows no joins

###In Access they can be permanent - Relationships

  • Save relationships
  • Open new query - show joins
  • Show that you can remove joins

Wednesday - Database Structure

Database Structure slides

Friday - Nested queries

Demonstrate by doing a query to get the number of trapping periods in each year.

  • First GROUP BY yr and COUNT period
  • Then GROUP BY yr and period
  • Save that query
  • Nest it to count the unique periods