SELECT c.nome FROM CLIENTE AS c
INNER JOIN VENDA AS v ON v.id_cliente = c.id
INNER JOIN ITEM_VENDA AS iv ON v.id = iv.id_venda
WHERE COUNT(*) > 3 GROUP BY c.nome

SELECT c.nome FROM CLIENTE AS c
INNER JOIN VENDA AS v ON v.id_cliente = c.id
INNER JOIN ITEM_VENDA AS iv ON v.id = iv.id_venda
WHERE iv.quantidade > 3
GROUP BY c.nome

SELECT c.nome FROM CLIENTE AS c
INNER JOIN VENDA AS v ON v.id_cliente = c.id
INNER JOIN ITEM_VENDA AS iv ON v.id = iv.id_venda
GROUP BY c.nome
HAVING COUNT(*) > 3

SELECT c.nome FROM CLIENTE AS c
INNER JOIN VENDA AS v ON v.id_cliente = c.id
GROUP BY c.nome
HAVING COUNT(*) > 3