1-- SELECT SUM(<column_name>) FROM <table_name> WHERE <condition>;
2SELECT SUM(amount) FROM invoices;
3SELECT client_name, SUM(amount) FROM invoices GROUP BY client_name;
1-- Sum Columns only show up in SELECT statement
2-- All other columns must be in both
3SELECT categories_column, SUM(units_column) AS total_units
4FROM schema.table
5GROUP BY categories_column;