How PHP calculates the sum of the data in a field of MySQL

How PHP calculates the sum of the data in a field of MySQL

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How PHP calculates the sum of the data in a field of MySQL

• phpUse foreach traversal to accumulate the fields you want to sum

• mysqlcan be used SUM

SELECT sum(`field_name`) FROM `table`

Now that you can use MySQL, why not just use the sum of MySQL?

PHP Write a foreach loop compile it again

Ask the question of the Lord, MySQL's sum is more efficient, or PHP's foreach faster.

The sum of the foreach computed data
foreach ($income as $key = = $val) {

        $total+= $val['xx'];              }

The sum () function of MySQL

Yes, why not use the SUM function, the select SUM('field') where ... data is a special point with some of the functions of MySQL in the format of a bit.

If it is a one-dimensional array direct array_sum
If it is a two-dimensional array can use Array_column, array_sum to do
It feels good to do it through MySQL.

It is usually an array, the direct count ($data) can find the total number of data

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