From aebf6e7fc17eb30167a343249bc279e91d8c680a Mon Sep 17 00:00:00 2001
From: "Grot (@grafanabot)" <43478413+grafanabot@users.noreply.github.com>
Date: Thu, 4 May 2023 14:29:05 +0100
Subject: [PATCH] [v9.5.x] InfluxDB: Fix adding FROM statement when the
 measurement is an empty string (#67835)

InfluxDB: Fix adding FROM statement when the measurement is an empty string (#67827)

* If the measurement empty don't add FROM statement

* Add comment line

(cherry picked from commit 764f87b4859a119942e889f051125fbf8f7f15c5)

Co-authored-by: ismail simsek <ismailsimsek09@gmail.com>
---
 .../app/plugins/datasource/influxdb/query_builder.ts  | 11 +++++++++--
 .../datasource/influxdb/specs/query_builder.test.ts   |  8 ++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/public/app/plugins/datasource/influxdb/query_builder.ts b/public/app/plugins/datasource/influxdb/query_builder.ts
index e62d4c818cf..60d190602da 100644
--- a/public/app/plugins/datasource/influxdb/query_builder.ts
+++ b/public/app/plugins/datasource/influxdb/query_builder.ts
@@ -64,7 +64,8 @@ export class InfluxQueryBuilder {
       measurement = this.target.measurement;
       policy = this.target.policy;
 
-      if (!measurement.match('^/.*/')) {
+      // If there is a measurement and it is not empty string
+      if (!measurement.match(/^\/.*\/|^$/)) {
         measurement = '"' + measurement + '"';
 
         if (policy && policy !== 'default') {
@@ -73,6 +74,10 @@ export class InfluxQueryBuilder {
         }
       }
 
+      if (measurement === '') {
+        return 'SHOW FIELD KEYS';
+      }
+
       return 'SHOW FIELD KEYS FROM ' + measurement;
     } else if (type === 'RETENTION POLICIES') {
       query = 'SHOW RETENTION POLICIES on "' + this.database + '"';
@@ -89,7 +94,9 @@ export class InfluxQueryBuilder {
         measurement = policy + '.' + measurement;
       }
 
-      query += ' FROM ' + measurement;
+      if (measurement !== '') {
+        query += ' FROM ' + measurement;
+      }
     }
 
     if (withKey) {
diff --git a/public/app/plugins/datasource/influxdb/specs/query_builder.test.ts b/public/app/plugins/datasource/influxdb/specs/query_builder.test.ts
index 07be475e028..17569325243 100644
--- a/public/app/plugins/datasource/influxdb/specs/query_builder.test.ts
+++ b/public/app/plugins/datasource/influxdb/specs/query_builder.test.ts
@@ -213,5 +213,13 @@ describe('InfluxQueryBuilder', () => {
       const query = builder.buildExploreQuery('TAG_KEYS');
       expect(query).toBe(`SHOW TAG KEYS WHERE "app" == ''`);
     });
+
+    it('should not add FROM statement if the measurement empty', () => {
+      const builder = new InfluxQueryBuilder({ measurement: '', tags: [] });
+      let query = builder.buildExploreQuery('TAG_KEYS');
+      expect(query).toBe('SHOW TAG KEYS');
+      query = builder.buildExploreQuery('FIELDS');
+      expect(query).toBe('SHOW FIELD KEYS');
+    });
   });
 });