Average and sum aggregators for Query Engine API

packages/core/content-manager/server/services/entity-manager.d.ts

@@ -4,6 +4,8 @@ interface EntityManager {
   findPage(): any;
   findWithRelationCounts(): any;
   count(): any;
+  sum(): any;
+  avg(): any;
   findOne(): any;
   findOneWithCreatorRoles(): any;
   create(): any;

packages/core/database/lib/entity-manager.js

@@ -154,6 +154,46 @@ const createEntityManager = db => {
       return result;
     },
 
+    async sum(uid, field, params = {}) {
+      await db.lifecycles.run('beforeSum', uid, { params });
+
+      if (!_.isString(field) || _.isEmpty(field)) {
+        throw new Error('Expects a field name to sum');
+      }
+
+      const res = await this.createQueryBuilder(uid)
+        .init(_.pick(['_q', 'where', 'filters'], params))
+        .sum(field)
+        .first()
+        .execute();
+
+      const result = Number(res.sum);
+
+      await db.lifecycles.run('afterSum', uid, { params, result });
+
+      return result;
+    },
+
+    async avg(uid, field, params = {}) {
+      await db.lifecycles.run('beforeAvg', uid, { params });
+
+      if (!_.isString(field) || _.isEmpty(field)) {
+        throw new Error('Expects a field name to average');
+      }
+
+      const res = await this.createQueryBuilder(uid)
+        .init(_.pick(['_q', 'where', 'filters'], params))
+        .avg(field)
+        .first()
+        .execute();
+
+      const result = Number(res.avg);
+
+      await db.lifecycles.run('afterAvg', uid, { params, result });
+
+      return result;
+    },
+
     async create(uid, params = {}) {
       await db.lifecycles.run('beforeCreate', uid, { params });
 

packages/core/database/lib/entity-repository.js

@@ -83,6 +83,14 @@ const createRepository = (uid, db) => {
       return db.entityManager.count(uid, params);
     },
 
+    sum(field, params) {
+      return db.entityManager.sum(uid, field, params);
+    },
+
+    avg(field, params) {
+      return db.entityManager.avg(uid, field, params);
+    },
+
     attachRelations(id, data) {
       return db.entityManager.attachRelations(uid, id, data);
     },

packages/core/database/lib/index.d.ts

@@ -72,6 +72,8 @@ interface EntityManager {
   deleteMany<K extends keyof AllTypes>(uid: K, params: any): Promise<{ count: number }>;
 
   count<K extends keyof AllTypes>(uid: K, params: any): Promise<number>;
+  sum<K extends keyof AllTypes>(uid: K, params: any): Promise<number>;
+  avg<K extends keyof AllTypes>(uid: K, params: any): Promise<number>;
 
   attachRelations<K extends keyof AllTypes>(uid: K, id: ID, data: any): Promise<any>;
   updateRelations<K extends keyof AllTypes>(uid: K, id: ID, data: any): Promise<any>;
@@ -107,6 +109,8 @@ interface QueryFromContentType<T extends keyof AllTypes> {
   deleteMany(params: any): Promise<{ count: number }>;
 
   count(params: any): Promise<number>;
+  sum(field: string, params: any): Promise<number>;
+  avg(field: string, params: any): Promise<number>;
 
   attachRelations(id: ID, data: any): Promise<any>;
   updateRelations(id: ID, data: any): Promise<any>;

packages/core/database/lib/lifecycles/index.d.ts

@@ -11,6 +11,10 @@ export type Action =
   | 'afterFindMany'
   | 'beforeCount'
   | 'afterCount'
+  | 'beforeSum'
+  | 'afterSum'
+  | 'beforeAvg'
+  | 'afterAvg'
   | 'beforeCreateMany'
   | 'afterCreateMany'
   | 'beforeUpdate'

packages/core/database/lib/query/query-builder.js

@@ -12,6 +12,8 @@ const createQueryBuilder = (uid, db) => {
     type: 'select',
     select: [],
     count: null,
+    sum: null,
+    avg: null,
     first: false,
     data: null,
     where: [],
@@ -75,6 +77,20 @@ const createQueryBuilder = (uid, db) => {
       return this;
     },
 
+    sum(sum) {
+      state.type = 'sum';
+      state.sum = sum;
+
+      return this;
+    },
+
+    avg(avg) {
+      state.type = 'avg';
+      state.avg = avg;
+
+      return this;
+    },
+
     where(where = {}) {
       if (!_.isPlainObject(where)) {
         throw new Error('Where must be an object');
@@ -174,7 +190,7 @@ const createQueryBuilder = (uid, db) => {
     },
 
     mustUseAlias() {
-      return ['select', 'count'].includes(state.type);
+      return ['select', 'count', 'sum', 'avg'].includes(state.type);
     },
 
     aliasColumn(key, alias) {
@@ -284,6 +300,14 @@ const createQueryBuilder = (uid, db) => {
           qb.count({ count: state.count });
           break;
         }
+        case 'sum': {
+          qb.sum({ sum: state.sum });
+          break;
+        }
+        case 'avg': {
+          qb.avg({ avg: state.avg });
+          break;
+        }
         case 'insert': {
           qb.insert(state.data);
 

packages/core/strapi/lib/core/domain/content-type/validator.js

@@ -12,6 +12,10 @@ const LIFECYCLES = [
   'afterFindMany',
   'beforeCount',
   'afterCount',
+  'beforeSum',
+  'afterSum',
+  'beforeAvg',
+  'afterAvg',
   'beforeCreateMany',
   'afterCreateMany',
   'beforeUpdate',