Combining SELECTs

So far, this book has covered topics such as regular expressions, aggregates, and joins. These powerful SQL features allow the construction of complex queries. In some cases, however, even these tools may prove inadequate. This chapter shows how SELECTs can be combined to create even more powerful queries.

 

• UNION, EXCEPT, and INTERSECT Clauses
• Subqueries
  • Subqueries as Constants
  • Subqueries as Correlated Values
  • Subqueries as Lists of Values
  • NOT IN and Subqueries with NULL Values
  • Subqueries Returning Multiple Columns
  • ANY, ALL, and EXISTS Clauses
  • Summary
• Outer Joins
• Subqueries in Non-SELECT Queries
• UPDATE with FROM
• Inserting Data Using SELECT
• Creating Tables Using SELECT
• Summary