1 files changed, 20 insertions, 0 deletions
diff --git a/content/posts/postgres-aggregates/aggregation.sql b/content/posts/postgres-aggregates/aggregation.sql
new file mode 100644
index 0000000..ebb9ed5
--- /dev/null
+++ b/content/posts/postgres-aggregates/aggregation.sql
@@ -0,0 +1,20 @@
+EXPLAIN (
+  ANALYZE,
+  COSTS,
+  VERBOSE,
+  BUFFERS
+)
+SELECT
+  products.id AS product_id,
+  products.name AS product_name,
+  COUNT(DISTINCT reviews.id) AS num_reviews,
+  COUNT(DISTINCT orders.id) AS num_orders
+FROM
+  products
+  LEFT JOIN reviews ON reviews.product_id = products.id
+  LEFT JOIN orders ON orders.product_id = products.id
+  -- WHERE
+  --   products.id % 10 = 0
+GROUP BY
+  products.id;
+