CREATE TABLE employees (first_name VARCHAR, last_name VARCHAR, id VARCHAR)
CREATE TABLE customers (support_rep_id VARCHAR)

Find the full name of employee who supported the most number of customers.
SELECT T1.first_name, T1.last_name FROM employees AS T1 JOIN customers AS T2 ON T1.id = T2.support_rep_id GROUP BY T1.id ORDER BY COUNT(*) DESC LIMIT 1
SELECT "T1"."first_name", "T1"."last_name" FROM "employees" AS "T1" JOIN "customers" AS "T2" ON "T1"."id" = "T2"."support_rep_id" GROUP BY "T1"."id" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1