CC SQL 12. summarizing Data

• Function Description
• AVG() Returns a column's average value
• COUNT() Returns the number of rows in a column
• MAX() Returns a column's highest value
• MIN() Returns a column's lowest value
• SUM() Returns the sum of a column's values

• The five aggregate functions can all be used in two ways:
• 1. To perform calculations on all rows, specify the ALL argument, or specify no argument at all (because ALL is the default behavior).
• 2. To only include unique values, specify the DISTINCT argument.

Tip ALL Is Default The ALL argument need not be specified because it is the default behavior. If DISTINCT is not specified, ALL is assumed.

• example:
• SELECT AVG(DISTINCT prod_price) AS avg_price
• FROM products
• WHERE vend_id = 1003;

• SELECT COUNT(*) AS num_items,
• MIN(prod_price) AS price_min,
• MAX(prod_price) AS price_max,
• AVG(prod_price) AS price_avg
• FROM products;