The SQL SELECT COUNT, SUM, and AVG syntax

The general COUNT syntax is:

1. SELECT COUNT(column–name)
2. FROM table–name

The general SUM syntax is:

1. SELECT SUM(column–name)
2. FROM table–name

The general AVG syntax is:

1. SELECT AVG(column–name)
2. FROM table–name

 

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SQL SELECT COUNT, SUM, and AVG Examples

Problem: Find the number of customers

1. SELECT COUNT(Id)
2. FROM Customer

Results:

Count
91

 

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Problem: Compute the total amount sold in 2013

1. SELECT SUM(TotalAmount)
2. FROM [Order]
3. WHERE YEAR(OrderDate) = 2013

Results:

Sum
658388.75

 

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Problem: Compute the average size of all orders

1. SELECT AVG(TotalAmount)
2. FROM [Order]

Results:

Average
1631.877819