fix builder for tables with no designated timestamp

Author: bziobrowski

src/data/QuestDbDatasource.ts

@@ -157,7 +157,7 @@ export class Datasource
     return view.map((item) => ({
       tableName: item[0],
       partitionBy: item[1],
-      designatedTimestamp: item[2],
+      designatedTimestamp: item[2] === null ? "" : item[2],
       walEnabled: item[3],
       dedup: item[4]
     }));

src/types.ts

@@ -119,10 +119,10 @@ export interface SqlBuilderOptionsList {
   table?: string;
   fields?: string[];
   filters?: Filter[];
+  partitionBy?: string[]
   orderBy?: OrderBy[];
   limit?: string;
   timeField: string;
-  partitionBy?: string[]
 }
 export enum BuilderMetricFieldAggregation {
   Sum = 'sum',