[GroupBy] Fix order by date granularity (#17573)

https://discord.com/channels/1130383047699738754/1466472357496623165/1466472357496623165

before
<img width="1262" height="598" alt="image"
src="https://github.com/user-attachments/assets/e6fb9a13-58c0-408d-b3e9-a486ec04c33c"
/>

after
<img width="670" height="267" alt="image"
src="https://github.com/user-attachments/assets/b4b5ab19-1144-4300-9801-b8220ce928f9"
/>

packages/twenty-server/src/engine/api/graphql/graphql-query-runner/graphql-query-parsers/graphql-query-order/graphql-query-order-group-by.parser.ts

@@ -21,7 +21,7 @@ import {
   type GroupByField,
   type GroupByRegularField,
 } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/types/group-by-field.types';
-import { getGroupByExpression } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/utils/get-group-by-expression.util';
+import { getGroupByOrderExpression } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/utils/get-group-by-order-expression.util';
 import { ProcessAggregateHelper } from 'src/engine/api/graphql/graphql-query-runner/helpers/process-aggregate.helper';
 import {
   type AggregationField,
@@ -493,7 +493,7 @@ export class GraphqlQueryOrderGroupByParser {
       )[0]
     }"`;
 
-    const expression = getGroupByExpression({
+    const expression = getGroupByOrderExpression({
       groupByField: associatedGroupByField,
       columnNameWithQuotes,
     });
@@ -620,7 +620,7 @@ export class GraphqlQueryOrderGroupByParser {
 
       const columnNameWithQuotes = `"${joinAlias}"."${nestedColumnName}"`;
 
-      const expression = getGroupByExpression({
+      const expression = getGroupByOrderExpression({
         groupByField: associatedGroupByField,
         columnNameWithQuotes,
       });

packages/twenty-server/src/engine/api/graphql/graphql-query-runner/group-by/resolvers/utils/get-group-by-order-expression.util.ts

@@ -0,0 +1,82 @@
+import {
+  FirstDayOfTheWeek,
+  ObjectRecordGroupByDateGranularity,
+} from 'twenty-shared/types';
+import { isDefined } from 'twenty-shared/utils';
+
+import { type GroupByField } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/types/group-by-field.types';
+import { getGroupByExpression } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/utils/get-group-by-expression.util';
+import { isGroupByDateField } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/utils/is-group-by-date-field.util';
+import { isGroupByRelationField } from 'src/engine/api/graphql/graphql-query-runner/group-by/resolvers/utils/is-group-by-relation-field.util';
+
+const DAYS_OF_WEEK = [
+  'Monday',
+  'Tuesday',
+  'Wednesday',
+  'Thursday',
+  'Friday',
+  'Saturday',
+  'Sunday',
+] as const;
+
+const getDayOfWeekOrderExpression = (
+  groupByExpression: string,
+  weekStartDay?: FirstDayOfTheWeek,
+): string => {
+  const startDay = weekStartDay ?? FirstDayOfTheWeek.MONDAY;
+
+  const startIndex =
+    startDay === FirstDayOfTheWeek.SUNDAY
+      ? 6
+      : startDay === FirstDayOfTheWeek.SATURDAY
+        ? 5
+        : 0;
+
+  const orderedDays = [
+    ...DAYS_OF_WEEK.slice(startIndex),
+    ...DAYS_OF_WEEK.slice(0, startIndex),
+  ];
+
+  const caseConditions = orderedDays
+    .map((day, index) => `WHEN '${day}' THEN ${index + 1}`)
+    .join(' ');
+
+  return `CASE ${groupByExpression} ${caseConditions} END`;
+};
+
+export const getGroupByOrderExpression = ({
+  groupByField,
+  columnNameWithQuotes,
+}: {
+  groupByField: GroupByField;
+  columnNameWithQuotes: string;
+}): string => {
+  if (
+    !(isGroupByDateField(groupByField) || isGroupByRelationField(groupByField))
+  ) {
+    return getGroupByExpression({ groupByField, columnNameWithQuotes });
+  }
+
+  const dateGranularity = groupByField.dateGranularity;
+
+  if (!isDefined(dateGranularity)) {
+    return getGroupByExpression({ groupByField, columnNameWithQuotes });
+  }
+
+  const groupByExpression = getGroupByExpression({
+    groupByField,
+    columnNameWithQuotes,
+  });
+
+  switch (dateGranularity) {
+    case ObjectRecordGroupByDateGranularity.DAY_OF_THE_WEEK:
+      return getDayOfWeekOrderExpression(
+        groupByExpression,
+        groupByField.weekStartDay,
+      );
+    case ObjectRecordGroupByDateGranularity.MONTH_OF_THE_YEAR:
+      return `CASE ${groupByExpression} WHEN 'January' THEN 1 WHEN 'February' THEN 2 WHEN 'March' THEN 3 WHEN 'April' THEN 4 WHEN 'May' THEN 5 WHEN 'June' THEN 6 WHEN 'July' THEN 7 WHEN 'August' THEN 8 WHEN 'September' THEN 9 WHEN 'October' THEN 10 WHEN 'November' THEN 11 WHEN 'December' THEN 12 END`;
+    default:
+      return groupByExpression;
+  }
+};