Add script to do statisical check on results

Signed-off-by: Alan Jowett <alan.jowett@microsoft.com>

scripts/check_perf_results.sql

@@ -0,0 +1,26 @@
+/*
+Copyright (c) Microsoft Corporation
+SPDX-License-Identifier: MIT
+*/
+WITH samples AS (
+    SELECT metric, value, "timestamp",
+           ROW_NUMBER() OVER (PARTITION BY metric ORDER BY "timestamp" DESC) AS row_num
+    FROM benchmarkresults
+    WHERE platform = 'Windows 2019'
+      AND repository = 'microsoft/ebpf-for-windows'
+      AND "timestamp" >= NOW() - INTERVAL '30 days'
+),
+stats AS (
+    SELECT metric,
+           AVG(value) as mean_value,
+           STDDEV(value) as stddev_value
+    FROM benchmarkresults
+    WHERE platform = 'Windows 2019'
+      AND repository = 'microsoft/ebpf-for-windows'
+      AND "timestamp" >= NOW() - INTERVAL '30 days'
+    GROUP BY metric
+)
+SELECT samples.timestamp, samples.metric, samples.value, stats.mean_value, stats.stddev_value
+FROM samples
+INNER JOIN stats ON samples.metric = stats.metric
+WHERE ABS(samples.value - stats.mean_value) >= 2 * stats.stddev_value AND row_num = 1;