how to use the count function in sql code example

Example 1: sql count

/*COUNT(column_name) will return the number of rows from the column 
that are not NULL*/
SELECT COUNT(column_name)
FROM table_name;

/*COUNT(*) will return the number of rows from the table*/
SELECT COUNT(*)
FROM table_name;

Example 2: To count number of rows in SQL table

SELECT count(*)
FROM information_schema.columns
WHERE table_name = 'Your_table_nale';

Example 3: sql count(*)

SELECT COUNT(column_name)
FROM table_name
WHERE condition;