SUM ​

Return the sum of the values for a numeric expression.

SUM(expression)

The expression must be numeric.

The following example calculates the total capacity for all of the stadiums used by London teams.

premdb=# SELECT SUM(capacity) FROM team WHERE city='London';
  sum   
--------
 296983
(1 row)

The following example returns the five cities that have the highest total stadium capacity:

premdb=# SELECT city, SUM(capacity) FROM team 
GROUP BY city ORDER BY 2 desc LIMIT 5;
   city    |  sum   
------------+--------
 London     | 296983
 Manchester | 130732
 Birmingham |  99801
 Liverpool  |  84963
 Sheffield  |  72434
(5 rows)

Return Types ​

The return type of the SUM function depends on the input type. The result is promoted where possible to prevent overflow errors.

• SUM(INT2) returns INT8
• SUM(INT4) returns INT8
• SUM(INT8) returns INT8
• SUM(FLOAT4) returns FLOAT8
• SUM(FLOAT8) returns FLOAT8
• AVG(DECIMAL(p,s)) returns DECIMAL(38,s)

Parent topic:Aggregate Functions