feat: allow logging the SQL query to stderr

- Logs the main SQL query when `log-query=main-query`.
- Only logs at the current `log-level`.

src/PostgREST/Query/QueryBuilder.hs

@@ -46,14 +46,14 @@ import Protolude
 readPlanToQuery :: ReadPlanTree -> SQL.Snippet
 readPlanToQuery node@(Node ReadPlan{select,from=mainQi,fromAlias,where_=logicForest,order, range_=readRange, relToParent, relJoinConds, relSelect} forest) =
   "SELECT " <>
-  intercalateSnippet ", " ((pgFmtSelectItem qi <$> (if null select && null forest then defSelect else select)) ++ joinsSelects) <> " " <>
-  fromFrag <> " " <>
-  intercalateSnippet " " joins <> " " <>
+  intercalateSnippet ", " ((pgFmtSelectItem qi <$> (if null select && null forest then defSelect else select)) ++ joinsSelects) <>
+  fromFrag <>
+  intercalateSnippet " " joins <>
   (if null logicForest && null relJoinConds
     then mempty
-    else "WHERE " <> intercalateSnippet " AND " (map (pgFmtLogicTree qi) logicForest ++ map pgFmtJoinCondition relJoinConds)) <> " " <>
-  groupF qi select relSelect <> " " <>
-  orderF qi order <> " " <>
+    else " WHERE " <> intercalateSnippet " AND " (map (pgFmtLogicTree qi) logicForest ++ map pgFmtJoinCondition relJoinConds)) <> " " <>
+  groupF qi select relSelect <>
+  orderF qi order <>
   limitOffsetF readRange
   where
     fromFrag = fromF relToParent mainQi fromAlias
@@ -94,7 +94,7 @@ getJoin :: RelSelectField -> ReadPlanTree -> SQL.Snippet
 getJoin fld node@(Node ReadPlan{relJoinType} _) =
   let
     correlatedSubquery sub al cond =
-      (if relJoinType == Just JTInner then "INNER" else "LEFT") <> " JOIN LATERAL ( " <> sub <> " ) AS " <> al <> " ON " <> cond
+      " " <> (if relJoinType == Just JTInner then "INNER" else "LEFT") <> " JOIN LATERAL ( " <> sub <> " ) AS " <> al <> " ON " <> cond
     subquery = readPlanToQuery node
     aggAlias = pgFmtIdent $ rsAggAlias fld
   in
@@ -258,7 +258,7 @@ getQualifiedIdentifier rel mainQi tblAlias = case rel of
 
 -- FROM clause plus implicit joins
 fromF :: Maybe Relationship -> QualifiedIdentifier -> Maybe Alias -> SQL.Snippet
-fromF rel mainQi tblAlias = "FROM " <>
+fromF rel mainQi tblAlias = " FROM " <>
   (case rel of
     -- Due to the use of CTEs on RPC, we need to cast the parameter to the table name in case of function overloading.
     -- See https://github.com/PostgREST/postgrest/issues/2963#issuecomment-1736557386

src/PostgREST/Query/Statements.hs

@@ -56,10 +56,11 @@ data ResultSet
 
 
 prepareWrite :: SQL.Snippet -> SQL.Snippet -> Bool -> Bool -> MediaType -> MediaHandler ->
-                Maybe PreferRepresentation -> Maybe PreferResolution -> [Text] -> Bool -> SQL.Statement () ResultSet
-prepareWrite selectQuery mutateQuery isInsert isPut mt handler rep resolution pKeys =
-  SQL.dynamicallyParameterized (mtSnippet mt snippet) decodeIt
+                Maybe PreferRepresentation -> Maybe PreferResolution -> [Text] -> Bool -> (SQL.Statement () ResultSet, ByteString)
+prepareWrite selectQuery mutateQuery isInsert isPut mt handler rep resolution pKeys prepared =
+ (result, sql)
  where
+  result@(SQL.Statement sql _ _ _) = SQL.dynamicallyParameterized (mtSnippet mt snippet) decodeIt prepared
   checkUpsert snip = if isInsert && (isPut || resolution == Just MergeDuplicates) then snip else "''"
   pgrstInsertedF = checkUpsert "nullif(current_setting('pgrst.inserted', true),'')::int"
   snippet =
@@ -93,10 +94,11 @@ prepareWrite selectQuery mutateQuery isInsert isPut mt handler rep resolution pK
     MTVndPlan{} -> planRow
     _           -> fromMaybe (RSStandard Nothing 0 mempty mempty Nothing Nothing Nothing) <$> HD.rowMaybe (standardRow False)
 
-prepareRead :: SQL.Snippet -> SQL.Snippet -> Bool -> MediaType -> MediaHandler -> Bool -> SQL.Statement () ResultSet
-prepareRead selectQuery countQuery countTotal mt handler =
-  SQL.dynamicallyParameterized (mtSnippet mt snippet) decodeIt
+prepareRead :: SQL.Snippet -> SQL.Snippet -> Bool -> MediaType -> MediaHandler -> Bool -> (SQL.Statement () ResultSet, ByteString)
+prepareRead selectQuery countQuery countTotal mt handler prepared =
+ (result, sql)
  where
+  result@(SQL.Statement sql _ _ _) = SQL.dynamicallyParameterized (mtSnippet mt snippet) decodeIt prepared
   snippet =
     "WITH " <> sourceCTE <> " AS ( " <> selectQuery <> " ) " <>
     countCTEF <> " " <>
@@ -118,10 +120,11 @@ prepareRead selectQuery countQuery countTotal mt handler =
 
 prepareCall :: Routine -> SQL.Snippet -> SQL.Snippet -> SQL.Snippet -> Bool ->
                MediaType -> MediaHandler -> Bool ->
-               SQL.Statement () ResultSet
-prepareCall rout callProcQuery selectQuery countQuery countTotal mt handler =
-  SQL.dynamicallyParameterized (mtSnippet mt snippet) decodeIt
+               (SQL.Statement () ResultSet, ByteString)
+prepareCall rout callProcQuery selectQuery countQuery countTotal mt handler prepared =
+  (result, sql)
   where
+    result@(SQL.Statement sql _ _ _) = SQL.dynamicallyParameterized (mtSnippet mt snippet) decodeIt prepared
     snippet =
       "WITH " <> sourceCTE <> " AS (" <> callProcQuery <> ") " <>
       countCTEF <>