@@ -956,7 +956,6 @@ defmodule Ecto.Query do
       Ecto.Query.exclude(query, :limit)
       Ecto.Query.exclude(query, :offset)
       Ecto.Query.exclude(query, :lock)
-      Ecto.Query.exclude(query, :label)
       Ecto.Query.exclude(query, :preload)
       Ecto.Query.exclude(query, :update)
       Ecto.Query.exclude(query, :windows)
@@ -1026,7 +1025,6 @@ defmodule Ecto.Query do
   defp do_exclude(%Ecto.Query{} = query, :limit), do: %{query | limit: nil}
   defp do_exclude(%Ecto.Query{} = query, :offset), do: %{query | offset: nil}
   defp do_exclude(%Ecto.Query{} = query, :lock), do: %{query | lock: nil}
-  defp do_exclude(%Ecto.Query{} = query, :label), do: %{query | label: nil}
   defp do_exclude(%Ecto.Query{} = query, :preload), do: %{query | preloads: [], assocs: []}
   defp do_exclude(%Ecto.Query{} = query, :update), do: %{query | updates: []}
   defp do_exclude(%Ecto.Query{} = query, :windows), do: %{query | windows: []}
@@ -1153,7 +1151,7 @@ defmodule Ecto.Query do
   end
 
   @from_join_opts [:as, :prefix, :hints]
-  @no_binds [:union, :union_all, :except, :except_all, :intersect, :intersect_all, :label]
+  @no_binds [:union, :union_all, :except, :except_all, :intersect, :intersect_all]
   @binds [:lock, :where, :or_where, :select, :distinct, :order_by, :group_by, :windows] ++
            [:having, :or_having, :limit, :offset, :preload, :update, :select_merge, :with_ctes]
 
@@ -2540,39 +2538,6 @@ defmodule Ecto.Query do
     Builder.Lock.build(query, binding, expr, __CALLER__)
   end
 
-  @doc ~S"""
-  A label query expression.
-
-  Adds the given text to the generated statement as a leading SQL comment,
-  immediately before the statement keyword:
-
-      /* get_username_q */ SELECT ...
-
-  This is useful to tag and identify queries in database logs and monitoring
-  tools. The label is rendered *leading* (rather than trailing) so it survives
-  truncation of long statements in logs.
-
-  Because the label becomes part of the generated SQL, it is also part of the
-  query cache key. Avoid highly dynamic values (such as per-request ids) as they
-  would defeat Ecto's prepared-statement caching; prefer a stable identifier per
-  call site.
-
-  ## Keywords example
-
-      from(p in Post, label: "get_post_titles_q", select: p.title)
-
-  ## Expressions example
-
-      Post |> label("get_post_titles_q") |> select([p], p.title)
-
-  ## Interpolation
-
-      report = "get_posts_q"
-      from(p in Post, label: ^report)
-  """
-  defmacro label(query, expr) do
-    Builder.Label.build(query, expr, __CALLER__)
-  end
 
   @doc ~S"""
   An update query expression.
 
@@ -124,7 +124,6 @@ defimpl Inspect, for: Ecto.Query do
     updates = kw_exprs(:update, query.updates, names)
 
     lock = kw_inspect(:lock, query.lock)
-    label = kw_inspect(:label, query.label)
     offset = kw_expr(:offset, query.offset, names)
     select = kw_expr(:select, query.select, names)
     distinct = kw_expr(:distinct, query.distinct, names)
@@ -141,7 +140,6 @@ defimpl Inspect, for: Ecto.Query do
       limit,
       offset,
       lock,
-      label,
       distinct,
       updates,
       select,
 
@@ -2383,6 +2383,36 @@ defmodule Ecto.Query.Planner do
 
   def attach_prefix(query, _), do: query
 
+  @doc """
+  Puts the label given via `opts` into the given query, if available.
+
+  The label is rendered by the adapter as a leading `/* ... */` SQL comment
+  and becomes part of the query cache key. It is embedded verbatim, so it may
+  not contain `/*`, `*/`, or null bytes.
+  """
+  def attach_label(%{label: nil} = query, opts) when is_list(opts) do
+    case Keyword.fetch(opts, :label) do
+      {:ok, label} -> %{query | label: validate_label!(label)}
+      :error -> query
+    end
+  end
+
+  def attach_label(query, _), do: query
+
+  defp validate_label!(label) when is_binary(label) do
+    if String.contains?(label, ["/*", "*/", <<0>>]) do
+      raise ArgumentError,
+            "a label cannot contain `/*`, `*/`, or null bytes, got: #{inspect(label)}. " <>
+              "Allowing them would let the label break out of the surrounding `/* */` comment"
+    end
+
+    label
+  end
+
+  defp validate_label!(other) do
+    raise ArgumentError, "a label must be a string, got: #{inspect(other)}"
+  end
+
   ## Helpers
 
   @all_exprs [
 
@@ -141,6 +141,12 @@ defmodule Ecto.Repo do
       in the cache and no cache update function will not be passed to the adapter. Note that
       this doesn't necessarily disable the database cache, it only affects Ecto's internal
       cache of normalized queries and adapter prepared statements. Defaults to `true`.
+    * `:label` - A string embedded into the generated statement as a leading SQL comment,
+      such as `/* import_users */ INSERT ...`, to identify the query in database logs and
+      monitoring tools. It is rendered leading (rather than trailing) so it survives truncation
+      of long statements in logs. The string is embedded verbatim and therefore cannot contain
+      `/*`, `*/`, or null bytes. The label becomes part of the query cache key, so prefer a
+      stable identifier per call site over highly dynamic values such as per-request ids.
 
   ## Adapter-Specific Errors
 
@@ -1581,13 +1587,6 @@ defmodule Ecto.Repo do
       in the schema. For more information see the ["Query Prefix"](`m:Ecto.Query#module-query-prefix`) section of the
       `Ecto.Query` documentation.
 
-    * `:label` - A string to tag the generated `UPDATE` with a leading SQL
-      comment, such as `/* bump_visits */ UPDATE ...`, to identify the statement
-      in database logs and monitoring tools. The string is embedded verbatim into
-      the SQL and therefore cannot contain `/*`, `*/`, or null bytes. Prefer a
-      stable identifier per call site, as the label becomes part of the query
-      cache key. See `Ecto.Query.label/2` to set it on the query itself instead.
-
   See the ["Shared options"](#module-shared-options) section at the module
   documentation for remaining options.
 
@@ -1637,13 +1636,6 @@ defmodule Ecto.Repo do
       in the schema. For more information see the ["Query Prefix"](`m:Ecto.Query#module-query-prefix`) section of the
       `Ecto.Query` documentation.
 
-    * `:label` - A string to tag the generated `DELETE` with a leading SQL
-      comment, such as `/* purge_stale */ DELETE ...`, to identify the statement
-      in database logs and monitoring tools. The string is embedded verbatim into
-      the SQL and therefore cannot contain `/*`, `*/`, or null bytes. Prefer a
-      stable identifier per call site, as the label becomes part of the query
-      cache key. See `Ecto.Query.label/2` to set it on the query itself instead.
-
   See the ["Shared options"](#module-shared-options) section at the module
   documentation for remaining options.
 
@@ -1746,13 +1738,6 @@ defmodule Ecto.Repo do
     * `:placeholders` - A map with placeholders. This feature is not supported
       by all databases. See the ["Placeholders" section](#c:insert_all/3-placeholders) for more information.
 
-    * `:label` - A string to tag the generated `INSERT` with a leading SQL
-      comment, such as `/* import_users */ INSERT ...`, to identify the statement
-      in database logs and monitoring tools. The string is embedded verbatim into
-      the SQL and therefore cannot contain `/*`, `*/`, or null bytes. Prefer a
-      stable identifier per call site, as the label becomes part of the query
-      cache key.
-
   See the ["Shared options"](#module-shared-options) section at the module
   documentation for remaining options.
 
 
@@ -6,7 +6,7 @@ defmodule Ecto.Repo.Queryable do
   alias Ecto.Query.Planner
   alias Ecto.Query.SelectExpr
 
-  import Ecto.Query.Planner, only: [attach_prefix: 2]
+  import Ecto.Query.Planner, only: [attach_prefix: 2, attach_label: 2]
 
   require Ecto.Query
 
@@ -37,7 +37,7 @@ defmodule Ecto.Repo.Queryable do
       |> Ecto.Query.Planner.ensure_select(true)
 
     {query, opts} = repo.prepare_query(:stream, query, opts)
-    query = attach_prefix(query, opts)
+    query = query |> attach_prefix(opts) |> attach_label(opts)
 
     query_cache? = Keyword.get(opts, :query_cache, true)
 
@@ -222,7 +222,7 @@ defmodule Ecto.Repo.Queryable do
     %{adapter: adapter, cache: cache, repo: repo} = adapter_meta
 
     {query, opts} = repo.prepare_query(operation, query, opts)
-    query = attach_prefix(query, opts)
+    query = query |> attach_prefix(opts) |> attach_label(opts)
 
     query_cache? = Keyword.get(opts, :query_cache, true)