fix(sql): use AST-based statement type detection for isSelectQuery

src/sql/recent-query.test.ts

@@ -46,6 +46,30 @@ test("isSelectQuery returns false for non-SELECT statements", () => {
   ).toBe(false);
 });
 
+test("isSelectQuery returns false for DML containing SELECT subqueries", () => {
+  expect(
+    RecentQuery.isSelectQuery(
+      makeRawQuery({
+        query: 'UPDATE "public"."oban_jobs" SET "state" = $1 FROM (SELECT id FROM t) s WHERE id = s.id',
+      }),
+    ),
+  ).toBe(false);
+  expect(
+    RecentQuery.isSelectQuery(
+      makeRawQuery({
+        query: "INSERT INTO archive SELECT * FROM users",
+      }),
+    ),
+  ).toBe(false);
+  expect(
+    RecentQuery.isSelectQuery(
+      makeRawQuery({
+        query: "DELETE FROM users WHERE EXISTS (SELECT 1 FROM banned)",
+      }),
+    ),
+  ).toBe(false);
+});
+
 // --- isSystemQuery ---
 
 test("isSystemQuery returns true for pg_ tables", () => {
@@ -193,3 +217,45 @@ test("analyze throws on unparseable SQL", async () => {
     RecentQuery.analyze(data, testHash, 3000),
   ).rejects.toThrow();
 });
+
+// --- statementType-based isSelectQuery via analyze ---
+
+test("analyze sets isSelectQuery=true for SELECT", async () => {
+  const data = makeRawQuery({ query: "SELECT * FROM users" });
+  const rq = await RecentQuery.analyze(data, testHash, 1000);
+  expect(rq.isSelectQuery).toBe(true);
+});
+
+test("analyze sets isSelectQuery=true for CTE with SELECT", async () => {
+  const data = makeRawQuery({
+    query: "WITH cte AS (SELECT id FROM users) SELECT * FROM cte",
+  });
+  const rq = await RecentQuery.analyze(data, testHash, 1000);
+  expect(rq.isSelectQuery).toBe(true);
+});
+
+test("analyze sets isSelectQuery=false for UPDATE even with SELECT subquery", async () => {
+  const data = makeRawQuery({
+    query:
+      'UPDATE "public"."jobs" SET "state" = $1 FROM (SELECT id FROM "public"."jobs" WHERE state = $2 LIMIT 10) AS s1 WHERE "jobs".id = s1.id',
+  });
+  const rq = await RecentQuery.analyze(data, testHash, 1000);
+  expect(rq.isSelectQuery).toBe(false);
+});
+
+test("analyze sets isSelectQuery=false for INSERT ... SELECT", async () => {
+  const data = makeRawQuery({
+    query: "INSERT INTO archive SELECT * FROM users WHERE active = false",
+  });
+  const rq = await RecentQuery.analyze(data, testHash, 1000);
+  expect(rq.isSelectQuery).toBe(false);
+});
+
+test("analyze sets isSelectQuery=false for DELETE with EXISTS subquery", async () => {
+  const data = makeRawQuery({
+    query:
+      "DELETE FROM users WHERE EXISTS (SELECT 1 FROM banned WHERE banned.user_id = users.id)",
+  });
+  const rq = await RecentQuery.analyze(data, testHash, 1000);
+  expect(rq.isSelectQuery).toBe(false);
+});

src/sql/recent-query.ts

@@ -8,6 +8,7 @@
   PostgresQueryBuilder,
   PssRewriter,
   SQLCommenterTag,
+  type StatementType,
   type TableReference,
 } from "@query-doctor/core";
 import { parse } from "@libpg-query/parser";
@@ -46,6 +47,7 @@
     readonly hash: QueryHash,
     readonly seenAt: number,
     analysisSkipped = false,
+    statementType?: StatementType,
   ) {
     this.username = data.username;
     this.query = data.query;
@@ -57,7 +59,9 @@
     this.analysisSkipped = analysisSkipped;
 
     this.isSystemQuery = RecentQuery.isSystemQuery(tableReferences);
-    this.isSelectQuery = RecentQuery.isSelectQuery(data);
+    this.isSelectQuery = statementType !== undefined
+      ? statementType === "select"
+      : RecentQuery.isSelectQuery(data);
     this.isIntrospection = RecentQuery.isIntrospection(data);
     this.isTargetlessSelectQuery = this.isSelectQuery
       ? RecentQuery.isTargetlessSelectQuery(tableReferences)
@@ -123,6 +127,8 @@
       analysis.nudges,
       hash,
       seenAt,
+      false,
+      analysis.statementType,
     );
   }
 
@@ -147,7 +153,7 @@
   }
 
   static isSelectQuery(data: RawRecentQuery): boolean {
-    return /select/i.test(data.query);
+    return /^\s*select/i.test(data.query);
   }
 
   static isSystemQuery(referencedTables: TableReference[]): boolean {