Explore table sizes

Let's start by exploring five related tables:

stackoverflow: questions asked on Stack Overflow with certain tags
company: information on companies related to tags in stackoverflow
tag_company: links stackoverflow to company
tag_type: type categories applied to tags in stackoverflow
fortune500: information on top US companies

Count the number of rows in a table with

SELECT count(*) 
  FROM tablename;

Count the number of columns in a table by selecting a few rows and manually counting the columns in the result.

Which table has the most rows? Which table has the most columns?

Possible Answers

stackoverflow has the most rows; company has the most columns
tag_company has the most rows; company has the most columns
stackoverflow has the most rows; fortune500 has the most columns
tag_type has the most rows; fortune500 has the most columns