feat: add support for filter during merge insert when matched (#948)

Closes #940

python/lancedb/merge.py

@@ -32,11 +32,14 @@ class LanceMergeInsertBuilder(object):
         self._table = table
         self._on = on
         self._when_matched_update_all = False
+        self._when_matched_update_all_condition = None
         self._when_not_matched_insert_all = False
         self._when_not_matched_by_source_delete = False
         self._when_not_matched_by_source_condition = None
 
-    def when_matched_update_all(self) -> LanceMergeInsertBuilder:
+    def when_matched_update_all(
+        self, *, where: Optional[str] = None
+    ) -> LanceMergeInsertBuilder:
         """
         Rows that exist in both the source table (new data) and
         the target table (old data) will be updated, replacing
@@ -47,6 +50,7 @@ class LanceMergeInsertBuilder(object):
         but that behavior is subject to change.
         """
         self._when_matched_update_all = True
+        self._when_matched_update_all_condition = where
         return self
 
     def when_not_matched_insert_all(self) -> LanceMergeInsertBuilder:

python/lancedb/remote/table.py

@@ -298,6 +298,10 @@ class RemoteTable(Table):
             )
         params["on"] = merge._on[0]
         params["when_matched_update_all"] = str(merge._when_matched_update_all).lower()
+        if merge._when_matched_update_all_condition is not None:
+            params[
+                "when_matched_update_all_filt"
+            ] = merge._when_matched_update_all_condition
         params["when_not_matched_insert_all"] = str(
             merge._when_not_matched_insert_all
         ).lower()

python/lancedb/table.py

@@ -1459,7 +1459,7 @@ class LanceTable(Table):
         ds = self.to_lance()
         builder = ds.merge_insert(merge._on)
         if merge._when_matched_update_all:
-            builder.when_matched_update_all()
+            builder.when_matched_update_all(merge._when_matched_update_all_condition)
         if merge._when_not_matched_insert_all:
             builder.when_not_matched_insert_all()
         if merge._when_not_matched_by_source_delete: