diff --git a/sqlx-test/src/lib.rs b/sqlx-test/src/lib.rs
index 4bbd7193..55e4b85c 100644
--- a/sqlx-test/src/lib.rs
+++ b/sqlx-test/src/lib.rs
@@ -185,7 +185,7 @@ macro_rules! MySql_query_for_test_prepared_type {
 #[macro_export]
 macro_rules! Mssql_query_for_test_prepared_type {
     () => {
-        "SELECT CASE WHEN {0} = @p1 THEN 1 ELSE 0 END, {0}, @p2"
+        "SELECT CASE WHEN {0} IS NULL AND @p1 IS NULL THEN 1 WHEN {0} = @p1 THEN 1 ELSE 0 END, {0}, @p2"
     };
 }