From ea6620b92c7b2a012e3ae9ad665a3d45a86c146a Mon Sep 17 00:00:00 2001
From: Dan Hansen <dan@recidiviz.org>
Date: Tue, 6 Feb 2024 14:37:25 -0800
Subject: [PATCH] [Functions] Fix NULLIF panic on null

---
 internal/function.go | 3 +++
 query_test.go        | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/internal/function.go b/internal/function.go
index 067a81f..2b0ba38 100644
--- a/internal/function.go
+++ b/internal/function.go
@@ -384,6 +384,9 @@ func IFNULL(expr, nullResult Value) (Value, error) {
 }
 
 func NULLIF(expr, exprToMatch Value) (Value, error) {
+	if expr == nil {
+		return nil, nil
+	}
 	cond, err := expr.EQ(exprToMatch)
 	if err != nil {
 		return nil, err
diff --git a/query_test.go b/query_test.go
index 515595e..bbb8417 100644
--- a/query_test.go
+++ b/query_test.go
@@ -470,6 +470,11 @@ FROM UNNEST([1, 2, 3, 4]) AS val`,
 			query:        `SELECT NULLIF(10, 0)`,
 			expectedRows: [][]interface{}{{int64(10)}},
 		},
+		{
+			name:         "nullif null",
+			query:        `SELECT NULLIF(null, 0)`,
+			expectedRows: [][]interface{}{{nil}},
+		},
 		{
 			name:         "rounding",
 			query:        `SELECT ROUND(2.0), ROUND(2.3), ROUND(2.8), ROUND(2.5), ROUND(-2.3), ROUND(-2.8), ROUND(-2.5)`,