fix isin behavior with left null

Author: TrevorBergeron

packages/bigframes/bigframes/core/compile/sqlglot/sqlglot_ir.py

@@ -385,9 +385,13 @@ def isin_join(
                 )
             )
         else:
-            new_column = sge.In(
-                this=conditions[0].expr,
-                expressions=[right._as_subquery()],
+            new_column = sge.func(
+                "COALESCE",
+                sge.In(
+                    this=conditions[0].expr,
+                    expressions=[right._as_subquery()],
+                ),
+                sql.literal(False, dtypes.BOOL_DTYPE),
             )
 
         new_column = sge.Alias(

packages/bigframes/tests/unit/core/compile/sqlglot/snapshots/test_compile_isin/test_compile_isin_not_nullable/out.sql

@@ -20,11 +20,11 @@ WITH `bfcte_0` AS (
 ), `bfcte_4` AS (
   SELECT
     *,
-    `bfcol_4` IN ((
+    COALESCE(`bfcol_4` IN ((
         SELECT
           *
         FROM `bfcte_3`
-    )) AS `bfcol_5`
+    )), FALSE) AS `bfcol_5`
   FROM `bfcte_1`
 )
 SELECT

packages/bigframes/tests/unit/core/compile/sqlglot/tpch/snapshots/test_tpch/test_tpch_query/16/out.sql

@@ -51,11 +51,11 @@ WITH `bfcte_0` AS (
 ), `bfcte_6` AS (
   SELECT
     *,
-    `bfcol_58` IN ((
+    COALESCE(`bfcol_58` IN ((
         SELECT
           *
         FROM `bfcte_5`
-    )) AS `bfcol_59`
+    )), FALSE) AS `bfcol_59`
   FROM `bfcte_4`
 ), `bfcte_7` AS (
   SELECT

packages/bigframes/tests/unit/core/compile/sqlglot/tpch/snapshots/test_tpch/test_tpch_query/18/out.sql

@@ -44,11 +44,11 @@ WITH `bfcte_0` AS (
 ), `bfcte_7` AS (
   SELECT
     *,
-    `bfcol_4` IN ((
+    COALESCE(`bfcol_4` IN ((
         SELECT
           *
         FROM `bfcte_6`
-    )) AS `bfcol_14`
+    )), FALSE) AS `bfcol_14`
   FROM `bfcte_2`
 ), `bfcte_8` AS (
   SELECT

packages/bigframes/tests/unit/core/compile/sqlglot/tpch/snapshots/test_tpch/test_tpch_query/20/out.sql

@@ -85,11 +85,11 @@ WITH `bfcte_0` AS (
 ), `bfcte_10` AS (
   SELECT
     *,
-    `bfcol_2` IN ((
+    COALESCE(`bfcol_2` IN ((
         SELECT
           *
         FROM `bfcte_8`
-    )) AS `bfcol_37`
+    )), FALSE) AS `bfcol_37`
   FROM `bfcte_1`
 ), `bfcte_11` AS (
   SELECT
@@ -127,11 +127,11 @@ WITH `bfcte_0` AS (
 ), `bfcte_15` AS (
   SELECT
     *,
-    `bfcol_41` IN ((
+    COALESCE(`bfcol_41` IN ((
         SELECT
           *
         FROM `bfcte_14`
-    )) AS `bfcol_62`
+    )), FALSE) AS `bfcol_62`
   FROM `bfcte_7`
 )
 SELECT

packages/bigframes/tests/unit/core/compile/sqlglot/tpch/snapshots/test_tpch/test_tpch_query/22/out.sql

@@ -92,11 +92,11 @@ WITH `bfcte_0` AS (
 ), `bfcte_12` AS (
   SELECT
     *,
-    `bfcol_61` IN ((
+    COALESCE(`bfcol_61` IN ((
         SELECT
           *
         FROM `bfcte_6`
-    )) AS `bfcol_64`
+    )), FALSE) AS `bfcol_64`
   FROM `bfcte_11`
 ), `bfcte_13` AS (
   SELECT