The difference between count (*) and count (field name) in SQL is detailed and uses

This article takes a detailed example to introduce the difference between count (*) and count (field name) in SQL, so you can refer to the following.

Previously did not pay attention to the difference between the two, look at the blog Park article, but also really caught my attention.

Data test: See figure

See the SQL statement:

SELECT COUNT (*) c1,COUNT from test

It is obvious that count (*) counts the total number of bars in the result set, and count (field name) counts the total number of columns that the field value is not NULL

The difference between count (*) and count (field name) in SQL is detailed and uses