Page 3 - SQL

Shorthand CASE in SELECT 11

CASE in a clause ORDER BY 11

Using CASE in UPDATE 12

CASE use for NULL values ordered last 12

CASE in ORDER BY clause to sort records by lowest value of 2 columns 13

Sample data 13

Query 13

Results 14

Explanation 14

Chapter 6: Clean Code in SQL 15

Introduction 15

Examples 15

Formatting and Spelling of Keywords and Names 15

Table/Column Names 15

Keywords 15

SELECT * 15

Indenting 16

Joins 17

Chapter 7: Comments 19

Examples 19

Single-line comments 19

Multi-line comments 19

Chapter 8: Common Table Expressions 20

Syntax 20

Remarks 20

Examples 20

Temporary query 20

recursively going up in a tree 21

generating values 21

recursively enumerating a subtree 22

Oracle CONNECT BY functionality with recursive CTEs 23