How to use sum() in mysql to find the sum of id fields?

Mysql uses sum() to find the sum of the id field: use "SELECT SUM(id) FROM data table name;" to find the sum of the id field and return the sum of the id field values; SUM() function When calculating, ignore rows with NULL column values.

(Recommended tutorial:mysql video tutorial)

The SUM() function returns the total number of numeric columns.

SQL SUM() Syntax

SELECT SUM(column_name) FROM table_name;

How does the SUM() function work?

• If you use the SUM function in a SELECT statement that returns no matching rows, the SUM function returns NULL instead of 0.

• The DISTINCT operator allows calculation of distinct values in a collection.

• The SUM function ignores NULL values in calculations.

[Example] Calculate the sum of the id fields in the tb_text table. The input SQL statement and execution results are as follows.

mysql> SELECT SUM(id) -> AS sum -> FROM tb_text; +-----------+ | sum | +-----------+ | 942 | +-----------+ 1 row in set (0.00 sec)

As you can see from the query results, the sum of the id fields returned by the SUM() function is 942.

Tip: The SUM() function ignores rows with NULL column values when calculating.

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