##### Computing Sum of Field Values

**SUM()** function computes the sum of all field values. Therefore the field should have the numerical data-type. The result returning by this function has the same data-type as the field, but the result accuracy can be higher.

What are the total *plan* and total real *sales* volume in the *company*?

SELECT SUM (quota), SUM (sales) FROM salesreps

##### Computing Average of Field Values.

**AVG** function computes the average of all field values. The field should have the numerical type. As **AVG** function first sums up all values contained in the field and then divide the sum on the number of these values, the result has double type.

Compute the average *goods*' price from *ACI* *producer*.

SELECT AVG (price) FROM products WHERE mfr_id = 'ACI'

##### Computing Extremes of Field Values

**MIN()** and **MAX()** functions allow to find correspondingly the less and the most values in the field.

The field can contain numerical or string values or date/time values. Result has the same data-type as the field itself.

SELECT MIN (quota), MAX (quota) FROM salesreps

Comparison of numbers, records, dates, time intervals occurs according to the standard rules.

##### Counting Values of Field.

**COUNT( *)** function counts the number of records in the resulting table.

Data-type of the field can be of any kind. This function always returns the fixed-point number irrespective of data-type of the field.

How many *clients* are there in the *company*?

SELECT COUNT ( * ) FROM customers

**COUNT(expr)** function counts the value number in the field.

How many *clients* are there in the *company*?

SELECT COUNT (cust_num) FROM customers

##### Computing BIT Functions for Values of Field.

**BIT_AND( expr )** Calculates **bitwise AND** for values of group. Returns value with all bits 1 if there is no records in the group.

**BIT_OR( expr )** Calculates **bitwise OR** for values of group. Returns zero (0)
if there is no records in the group.

**BIT_XOR( expr )** Calculates **bitwise OR** for values of group. Returns zero (0) if there is no records in the group.