diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9b5d62b..88260e6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+
+- fix query encoding for datetimes where the microseconds value starts with zeroes `~U[****-**-** **:**:**.0*****]` https://github.com/plausible/ch/pull/175
+
 ## 0.2.5 (2024-03-05)
 
 - add `:data` in `%Ch.Result{}` https://github.com/plausible/ch/pull/159
@@ -10,7 +14,7 @@
 ## 0.2.4 (2024-01-29)
 
 - use `ch-#{version}` as user-agent https://github.com/plausible/ch/pull/154
-- fix query string escaping for `\t`, `\\`, and `\n` https://github.com/plausible/ch/pull/155 
+- fix query string escaping for `\t`, `\\`, and `\n` https://github.com/plausible/ch/pull/155
 
 ## 0.2.3 (2024-01-29)
 
diff --git a/lib/ch/query.ex b/lib/ch/query.ex
index 66f7c83..4aaf5bb 100644
--- a/lib/ch/query.ex
+++ b/lib/ch/query.ex
@@ -232,7 +232,7 @@ defimpl DBConnection.Query, for: Ch.Query do
         IO.iodata_to_binary([
           Integer.to_string(seconds),
           ?.,
-          String.pad_leading(Integer.to_string(fractional), precision)
+          String.pad_leading(Integer.to_string(fractional), precision, "0")
         ])
 
       _ ->
diff --git a/test/ch/connection_test.exs b/test/ch/connection_test.exs
index da5f39a..1578220 100644
--- a/test/ch/connection_test.exs
+++ b/test/ch/connection_test.exs
@@ -152,6 +152,16 @@ defmodule Ch.ConnectionTest do
              [[~N[2021-01-01 12:00:00.000000], to_string(naive)]]
   end
 
+  test "utc datetime64 microseconds with more precision than digits", %{conn: conn} do
+    # this test case guards against a previous bug where DateTimes with a microsecond value of with N digits
+    # and a precision > N would be encoded with a space like `234235234. 234123`
+    utc = ~U[2024-05-26 20:00:46.099856Z]
+    naive = utc |> DateTime.shift_zone!(Ch.Test.clickhouse_tz(conn)) |> DateTime.to_naive()
+
+    assert Ch.query!(conn, "select {$0:DateTime64(6)} as d, toString(d)", [utc]).rows ==
+             [[~N[2024-05-26 20:00:46.099856Z], to_string(naive)]]
+  end
+
   test "select with options", %{conn: conn} do
     assert {:ok, %{num_rows: 1, rows: [["async_insert", "Bool", "1"]]}} =
              Ch.query(conn, "show settings like 'async_insert'", [], settings: [async_insert: 1])