diff --git a/crates/squawk_parser/src/grammar.rs b/crates/squawk_parser/src/grammar.rs
index c6808c32..4603a7ad 100644
--- a/crates/squawk_parser/src/grammar.rs
+++ b/crates/squawk_parser/src/grammar.rs
@@ -877,11 +877,7 @@ fn exists_fn(p: &mut Parser<'_>) -> CompletedMarker {
     let m = p.start();
     p.bump(EXISTS_KW);
     p.expect(L_PAREN);
-    if p.at_ts(SELECT_FIRST) {
-        select(p, None, &SelectRestrictions::default(), false);
-    } else {
-        p.error("expected select");
-    }
+    query(p);
     p.expect(R_PAREN);
     let m = m.complete(p, EXISTS_FN).precede(p);
     opt_agg_clauses(p);
@@ -10024,7 +10020,7 @@ fn create_role(p: &mut Parser<'_>) -> CompletedMarker {
 
 fn select_insert_delete_update_or_notify(p: &mut Parser<'_>, semi_allowed: bool) {
     // statement
-    // Any SELECT, INSERT, UPDATE, DELETE, MERGE, or VALUES statement.
+    // Any SELECT, INSERT, UPDATE, DELETE, NOTIFY, or VALUES statement.
     let statement = stmt(
         p,
         &StmtRestrictions {
@@ -10034,7 +10030,8 @@ fn select_insert_delete_update_or_notify(p: &mut Parser<'_>, semi_allowed: bool)
     );
     if let Some(statement) = statement {
         match statement.kind() {
-            SELECT | VALUES | INSERT | UPDATE | DELETE | NOTIFY => (),
+            SELECT | COMPOUND_SELECT | PAREN_SELECT | TABLE | VALUES | INSERT | UPDATE | DELETE
+            | NOTIFY => (),
             kind => {
                 p.error(format!(
                     "expected SELECT, INSERT, UPDATE, DELETE, NOTIFY, or VALUES statement, got {kind:?}"
@@ -11148,7 +11145,7 @@ fn explain(p: &mut Parser<'_>) -> CompletedMarker {
 }
 
 fn opt_explain_option_list(p: &mut Parser<'_>) -> Option<CompletedMarker> {
-    if !p.at(L_PAREN) || (p.at(L_PAREN) && p.nth_at_ts(1, SELECT_FIRST)) {
+    if !p.at(L_PAREN) || p.nth_at_ts(1, PAREN_SELECT_FIRST) {
         return None;
     }
     let m = p.start();
diff --git a/crates/squawk_parser/tests/data/ok/create_rule.sql b/crates/squawk_parser/tests/data/ok/create_rule.sql
index a05c8bf6..fadad310 100644
--- a/crates/squawk_parser/tests/data/ok/create_rule.sql
+++ b/crates/squawk_parser/tests/data/ok/create_rule.sql
@@ -16,6 +16,16 @@ create or replace rule r as on select
     notify f;
   );
 
+-- select_stmt_variants
+create rule r as on insert to t do instead ((select 1));
+create rule r as on insert to t do also ((select 1));
+create rule r as on insert to t do instead (notify foo; (select 1););
+create rule r as on insert to t do instead ((select 1) union (select 2););
+create rule r as on insert to t do instead select 1 union select 2;
+create rule r as on insert to t do instead (select 1 union select 2;);
+create rule r as on insert to t do instead table t;
+create rule r as on insert to t do instead (table t;);
+
 -- doc_1
 CREATE RULE "_RETURN" AS
     ON SELECT TO t1
diff --git a/crates/squawk_parser/tests/data/ok/explain.sql b/crates/squawk_parser/tests/data/ok/explain.sql
index e0719639..305ac9e2 100644
--- a/crates/squawk_parser/tests/data/ok/explain.sql
+++ b/crates/squawk_parser/tests/data/ok/explain.sql
@@ -74,9 +74,12 @@ EXPLAIN (GENERIC_PLAN)
 
 -- parens_select
 explain analyze (((((select 1)))));
+explain ((select 1));
+explain ((select 1) union (select 2));
 
 -- parens_values
 explain analyze (((((values (1))))));
+explain ((values (1)));
 
 -- boolean off
 EXPLAIN (COSTS OFF) SELECT * FROM foo WHERE i = 4;
diff --git a/crates/squawk_parser/tests/data/ok/select_funcs.sql b/crates/squawk_parser/tests/data/ok/select_funcs.sql
index 6fd03406..34c9ef96 100644
--- a/crates/squawk_parser/tests/data/ok/select_funcs.sql
+++ b/crates/squawk_parser/tests/data/ok/select_funcs.sql
@@ -144,6 +144,10 @@ select json_scalar(1);
 
 -- exists
 select exists(select 1 from t where a = b);
+select exists((select 1));
+select exists(((select 1)));
+select exists((select 1) union (select 2));
+select exists((table t));
 
 select exists(with t as (select 1) select * from t);
 
diff --git a/crates/squawk_parser/tests/snapshots/tests__create_rule_ok.snap b/crates/squawk_parser/tests/snapshots/tests__create_rule_ok.snap
index 0e51b70b..5acc8459 100644
--- a/crates/squawk_parser/tests/snapshots/tests__create_rule_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__create_rule_ok.snap
@@ -211,6 +211,384 @@ SOURCE_FILE
         R_PAREN ")"
     SEMICOLON ";"
   WHITESPACE "\n\n"
+  COMMENT "-- select_stmt_variants"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      RULE_STMT_LIST
+        L_PAREN "("
+        PAREN_SELECT
+          L_PAREN "("
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "1"
+          R_PAREN ")"
+        R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      ALSO_KW "also"
+      WHITESPACE " "
+      RULE_STMT_LIST
+        L_PAREN "("
+        PAREN_SELECT
+          L_PAREN "("
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "1"
+          R_PAREN ")"
+        R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      RULE_STMT_LIST
+        L_PAREN "("
+        NOTIFY
+          NOTIFY_KW "notify"
+          WHITESPACE " "
+          NAME_REF
+            IDENT "foo"
+          SEMICOLON ";"
+        WHITESPACE " "
+        PAREN_SELECT
+          L_PAREN "("
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "1"
+          R_PAREN ")"
+          SEMICOLON ";"
+        R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      RULE_STMT_LIST
+        L_PAREN "("
+        COMPOUND_SELECT
+          PAREN_SELECT
+            L_PAREN "("
+            SELECT
+              SELECT_CLAUSE
+                SELECT_KW "select"
+                WHITESPACE " "
+                TARGET_LIST
+                  TARGET
+                    LITERAL
+                      INT_NUMBER "1"
+            R_PAREN ")"
+          WHITESPACE " "
+          UNION_KW "union"
+          WHITESPACE " "
+          PAREN_SELECT
+            L_PAREN "("
+            SELECT
+              SELECT_CLAUSE
+                SELECT_KW "select"
+                WHITESPACE " "
+                TARGET_LIST
+                  TARGET
+                    LITERAL
+                      INT_NUMBER "2"
+            R_PAREN ")"
+          SEMICOLON ";"
+        R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      COMPOUND_SELECT
+        SELECT
+          SELECT_CLAUSE
+            SELECT_KW "select"
+            WHITESPACE " "
+            TARGET_LIST
+              TARGET
+                LITERAL
+                  INT_NUMBER "1"
+        WHITESPACE " "
+        UNION_KW "union"
+        WHITESPACE " "
+        SELECT
+          SELECT_CLAUSE
+            SELECT_KW "select"
+            WHITESPACE " "
+            TARGET_LIST
+              TARGET
+                LITERAL
+                  INT_NUMBER "2"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      RULE_STMT_LIST
+        L_PAREN "("
+        COMPOUND_SELECT
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "1"
+          WHITESPACE " "
+          UNION_KW "union"
+          WHITESPACE " "
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "2"
+          SEMICOLON ";"
+        R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      TABLE
+        TABLE_KW "table"
+        WHITESPACE " "
+        RELATION_NAME
+          PATH
+            PATH_SEGMENT
+              NAME_REF
+                IDENT "t"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  CREATE_RULE
+    CREATE_KW "create"
+    WHITESPACE " "
+    RULE_KW "rule"
+    WHITESPACE " "
+    NAME
+      IDENT "r"
+    WHITESPACE " "
+    AS_KW "as"
+    WHITESPACE " "
+    RULE_ON
+      ON_KW "on"
+      WHITESPACE " "
+      INSERT_KW "insert"
+      WHITESPACE " "
+      TO_KW "to"
+      WHITESPACE " "
+      PATH
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "t"
+    WHITESPACE " "
+    RULE_DO
+      DO_KW "do"
+      WHITESPACE " "
+      INSTEAD_KW "instead"
+      WHITESPACE " "
+      RULE_STMT_LIST
+        L_PAREN "("
+        TABLE
+          TABLE_KW "table"
+          WHITESPACE " "
+          RELATION_NAME
+            PATH
+              PATH_SEGMENT
+                NAME_REF
+                  IDENT "t"
+          SEMICOLON ";"
+        R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n\n"
   COMMENT "-- doc_1"
   WHITESPACE "\n"
   CREATE_RULE
diff --git a/crates/squawk_parser/tests/snapshots/tests__explain_ok.snap b/crates/squawk_parser/tests/snapshots/tests__explain_ok.snap
index 03b4a2e6..e1e2c5fb 100644
--- a/crates/squawk_parser/tests/snapshots/tests__explain_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__explain_ok.snap
@@ -761,6 +761,59 @@ SOURCE_FILE
         R_PAREN ")"
       R_PAREN ")"
     SEMICOLON ";"
+  WHITESPACE "\n"
+  EXPLAIN
+    EXPLAIN_KW "explain"
+    WHITESPACE " "
+    PAREN_SELECT
+      L_PAREN "("
+      PAREN_SELECT
+        L_PAREN "("
+        SELECT
+          SELECT_CLAUSE
+            SELECT_KW "select"
+            WHITESPACE " "
+            TARGET_LIST
+              TARGET
+                LITERAL
+                  INT_NUMBER "1"
+        R_PAREN ")"
+      R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  EXPLAIN
+    EXPLAIN_KW "explain"
+    WHITESPACE " "
+    PAREN_SELECT
+      L_PAREN "("
+      COMPOUND_SELECT
+        PAREN_SELECT
+          L_PAREN "("
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "1"
+          R_PAREN ")"
+        WHITESPACE " "
+        UNION_KW "union"
+        WHITESPACE " "
+        PAREN_SELECT
+          L_PAREN "("
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "2"
+          R_PAREN ")"
+      R_PAREN ")"
+    SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- parens_values"
   WHITESPACE "\n"
@@ -794,6 +847,26 @@ SOURCE_FILE
         R_PAREN ")"
       R_PAREN ")"
     SEMICOLON ";"
+  WHITESPACE "\n"
+  EXPLAIN
+    EXPLAIN_KW "explain"
+    WHITESPACE " "
+    PAREN_SELECT
+      L_PAREN "("
+      PAREN_SELECT
+        L_PAREN "("
+        VALUES
+          VALUES_KW "values"
+          WHITESPACE " "
+          ROW_LIST
+            ROW
+              L_PAREN "("
+              LITERAL
+                INT_NUMBER "1"
+              R_PAREN ")"
+        R_PAREN ")"
+      R_PAREN ")"
+    SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- boolean off"
   WHITESPACE "\n"
diff --git a/crates/squawk_parser/tests/snapshots/tests__select_funcs_ok.snap b/crates/squawk_parser/tests/snapshots/tests__select_funcs_ok.snap
index dfaf7a6b..c1c3f5eb 100644
--- a/crates/squawk_parser/tests/snapshots/tests__select_funcs_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__select_funcs_ok.snap
@@ -2480,6 +2480,120 @@ SOURCE_FILE
                       IDENT "b"
               R_PAREN ")"
     SEMICOLON ";"
+  WHITESPACE "\n"
+  SELECT
+    SELECT_CLAUSE
+      SELECT_KW "select"
+      WHITESPACE " "
+      TARGET_LIST
+        TARGET
+          CALL_EXPR
+            EXISTS_FN
+              EXISTS_KW "exists"
+              L_PAREN "("
+              PAREN_SELECT
+                L_PAREN "("
+                SELECT
+                  SELECT_CLAUSE
+                    SELECT_KW "select"
+                    WHITESPACE " "
+                    TARGET_LIST
+                      TARGET
+                        LITERAL
+                          INT_NUMBER "1"
+                R_PAREN ")"
+              R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  SELECT
+    SELECT_CLAUSE
+      SELECT_KW "select"
+      WHITESPACE " "
+      TARGET_LIST
+        TARGET
+          CALL_EXPR
+            EXISTS_FN
+              EXISTS_KW "exists"
+              L_PAREN "("
+              PAREN_SELECT
+                L_PAREN "("
+                PAREN_SELECT
+                  L_PAREN "("
+                  SELECT
+                    SELECT_CLAUSE
+                      SELECT_KW "select"
+                      WHITESPACE " "
+                      TARGET_LIST
+                        TARGET
+                          LITERAL
+                            INT_NUMBER "1"
+                  R_PAREN ")"
+                R_PAREN ")"
+              R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  SELECT
+    SELECT_CLAUSE
+      SELECT_KW "select"
+      WHITESPACE " "
+      TARGET_LIST
+        TARGET
+          CALL_EXPR
+            EXISTS_FN
+              EXISTS_KW "exists"
+              L_PAREN "("
+              COMPOUND_SELECT
+                PAREN_SELECT
+                  L_PAREN "("
+                  SELECT
+                    SELECT_CLAUSE
+                      SELECT_KW "select"
+                      WHITESPACE " "
+                      TARGET_LIST
+                        TARGET
+                          LITERAL
+                            INT_NUMBER "1"
+                  R_PAREN ")"
+                WHITESPACE " "
+                UNION_KW "union"
+                WHITESPACE " "
+                PAREN_SELECT
+                  L_PAREN "("
+                  SELECT
+                    SELECT_CLAUSE
+                      SELECT_KW "select"
+                      WHITESPACE " "
+                      TARGET_LIST
+                        TARGET
+                          LITERAL
+                            INT_NUMBER "2"
+                  R_PAREN ")"
+              R_PAREN ")"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  SELECT
+    SELECT_CLAUSE
+      SELECT_KW "select"
+      WHITESPACE " "
+      TARGET_LIST
+        TARGET
+          CALL_EXPR
+            EXISTS_FN
+              EXISTS_KW "exists"
+              L_PAREN "("
+              PAREN_SELECT
+                L_PAREN "("
+                TABLE
+                  TABLE_KW "table"
+                  WHITESPACE " "
+                  RELATION_NAME
+                    PATH
+                      PATH_SEGMENT
+                        NAME_REF
+                          IDENT "t"
+                R_PAREN ")"
+              R_PAREN ")"
+    SEMICOLON ";"
   WHITESPACE "\n\n"
   SELECT
     SELECT_CLAUSE