Answers for "get count of column in sql"

sql count column

-- Oracle
SELECT count(*) FROM ALL_TAB_COLUMNS WHERE OWNER='owner_name' 
	AND TABLE_NAME = 'table_name';
-- SQL Server / MySQL
SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'schema_name' 
	AND TABLE_NAME = 'table_name';

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;