diff --git a/authors/Guilhermevalenca/01.sql b/authors/Guilhermevalenca/01.sql
new file mode 100644
index 0000000..9453dd2
--- /dev/null
+++ b/authors/Guilhermevalenca/01.sql
@@ -0,0 +1 @@
+select * from products;
\ No newline at end of file
diff --git a/authors/Guilhermevalenca/02.sql b/authors/Guilhermevalenca/02.sql
new file mode 100644
index 0000000..a18ffd9
--- /dev/null
+++ b/authors/Guilhermevalenca/02.sql
@@ -0,0 +1,8 @@
+select
+	products.*,
+	suppliers.company_name
+from
+	products
+left join 
+	suppliers
+	on products.supplier_id = suppliers.supplier_id;
\ No newline at end of file
diff --git a/authors/Guilhermevalenca/03.sql b/authors/Guilhermevalenca/03.sql
new file mode 100644
index 0000000..abb13ef
--- /dev/null
+++ b/authors/Guilhermevalenca/03.sql
@@ -0,0 +1,10 @@
+select 
+	*,
+	customers.company_name,
+	concat(employees.first_name, ' ', employees.last_name) as full_name
+from 
+	orders
+left join
+	customers on orders.customer_id = customers.customer.id
+left join
+	employees on orders.employee_id = employees.employee.id;
diff --git a/authors/Guilhermevalenca/04.sql b/authors/Guilhermevalenca/04.sql
new file mode 100644
index 0000000..bbd8af2
--- /dev/null
+++ b/authors/Guilhermevalenca/04.sql
@@ -0,0 +1,10 @@
+select 
+	*,
+	categories.category_name,
+	suppliers.company_name
+from
+	products
+left join
+	categories on products.category_id = categories.category_id
+left join 
+	suppliers on products.supplier_id = suppliers.supplier_id;
\ No newline at end of file
diff --git a/authors/Guilhermevalenca/05.sql b/authors/Guilhermevalenca/05.sql
new file mode 100644
index 0000000..eece083
--- /dev/null
+++ b/authors/Guilhermevalenca/05.sql
@@ -0,0 +1,8 @@
+select 
+	customers.company_name,
+	count(orders.order_id) as total_orders 
+from
+	customers
+left join
+	orders on customers.customer_id = orders.customer_id
+group by customers.company_name;
\ No newline at end of file
diff --git a/authors/Guilhermevalenca/06.sql b/authors/Guilhermevalenca/06.sql
new file mode 100644
index 0000000..0be2245
--- /dev/null
+++ b/authors/Guilhermevalenca/06.sql
@@ -0,0 +1,11 @@
+select 
+	concat(employees.first_name, ' ', employees.last_name) as name,
+	'R$ ' || round( cast( sum(order_details.quantity * order_details.unit_price) as numeric), 2) as total_sales
+from 
+	employees
+left join 
+	orders on orders.employee_id = employees.employee_id
+left join
+	order_details on order_details.order_id = orders.order_id
+group by
+	name;
\ No newline at end of file
diff --git a/authors/Guilhermevalenca/07.sql b/authors/Guilhermevalenca/07.sql
new file mode 100644
index 0000000..0e4ef10
--- /dev/null
+++ b/authors/Guilhermevalenca/07.sql
@@ -0,0 +1,9 @@
+select
+	categories.category_name,
+	'R$ ' || trunc( cast( avg(products.unit_price) as numeric), 2) as average_pre_product
+from 
+	categories
+left join 
+	products on categories.category_id = products.category_id
+group by
+	categories.category_name;
\ No newline at end of file
diff --git a/authors/Guilhermevalenca/08.sql b/authors/Guilhermevalenca/08.sql
new file mode 100644
index 0000000..11dbf19
--- /dev/null
+++ b/authors/Guilhermevalenca/08.sql
@@ -0,0 +1,10 @@
+select
+	customers.company_name
+from
+	customers
+left join 
+	orders on orders.customer_id = customers.customer_id
+where
+	orders.order_id is null
+group by
+	customers.company_name;
\ No newline at end of file