diff --git a/CHANGELOG.md b/CHANGELOG.md
index fc823a755..b1a09526f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # CHANGELOG.md
 
 ## v0.47.0 (unreleased)
+- Updated sqlx-oldapi to v0.6.57 to fix SQL Server fallback expressions such as `ISNULL($missing, 'default')` truncating defaults or failing for date values when the bound variable is `NULL`.
 - Fixed MSSQL `JSON_OBJECT('key': value)` expressions being rejected by SQLPage's parser, including when used in `SET` statements or nested in `sqlpage.*` function calls.
 - OIDC now checks both normalized request paths and their resolved SQL files against protected prefixes, closing authentication bypasses through path and clean-URL aliases. Nonce verification also rejects provider-returned Argon2 parameters outside SQLPage's fixed low-cost profile before hashing.
 - `cargo install sqlpage`, and any build from the crates.io tarball, no longer needs internet access. The browser libraries now come from npm and ship inside the published crate. Building from a git checkout needs `npm ci` first. Pre-built binaries and the Docker image are unaffected.
diff --git a/Cargo.lock b/Cargo.lock
index ba088d137..22edbbf63 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4606,9 +4606,9 @@ dependencies = [
 
 [[package]]
 name = "sqlx-core-oldapi"
-version = "0.6.56"
+version = "0.6.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e33eb18d1e750df8aef99361ee02e170562dff119108680bc9035e796cd2a84"
+checksum = "a9cf228e0312c68be3bf5fe175305e28127a18a2d5231d1ed51888bfbbcfa8e9"
 dependencies = [
  "ahash",
  "atoi 2.0.0",
@@ -4669,9 +4669,9 @@ dependencies = [
 
 [[package]]
 name = "sqlx-rt-oldapi"
-version = "0.6.56"
+version = "0.6.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b8d629fed8792460ff39bb58cb154bfe181893ab9a51d0a3634950b35672a57"
+checksum = "ef74464ebe407e3e2a81013ede45cb60ebb3e5fe23f771bd68e3d1941558d542"
 dependencies = [
  "once_cell",
  "tokio",
diff --git a/Cargo.toml b/Cargo.toml
index c1864fa9b..7b29ee23c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -37,7 +37,7 @@ panic = "abort"
 codegen-units = 2
 
 [dependencies]
-sqlx = { package = "sqlx-core-oldapi", version = "0.6.56", default-features = false, features = [
+sqlx = { package = "sqlx-core-oldapi", version = "0.6.57", default-features = false, features = [
     "any",
     "runtime-tokio-rustls",
     "migrate",
diff --git a/tests/sql_test_files/data/database-specific/mssql/null_variable_fallback.sql b/tests/sql_test_files/data/database-specific/mssql/null_variable_fallback.sql
new file mode 100644
index 000000000..a0d27034d
--- /dev/null
+++ b/tests/sql_test_files/data/database-specific/mssql/null_variable_fallback.sql
@@ -0,0 +1,8 @@
+SELECT
+    CONCAT(
+        'isnull=[', ISNULL($missing, 'hello'),
+        '] coalesce=[', COALESCE($missing, 'hello'),
+        '] len=', LEN(ISNULL($missing, 'hello')),
+        '; date_is_date=', ISDATE(ISNULL($missing_date, GETDATE()))
+    ) AS actual,
+    'isnull=[hello] coalesce=[hello] len=5; date_is_date=1' AS expected;