Added withCount cross database support

Author: maguilar92

src/Eloquent/Builder.php

@@ -10,5 +10,6 @@ class Builder extends IlluminateEloquentBuilder
 {
     use IlluminateEloquentQueriesRelationships, CrossDatabaseQueriesRelationships {
         CrossDatabaseQueriesRelationships::addHasWhere insteadof IlluminateEloquentQueriesRelationships;
+        CrossDatabaseQueriesRelationships::withCount insteadof IlluminateEloquentQueriesRelationships;
     }
 }

src/Eloquent/Concerns/QueriesRelationships.php

@@ -5,6 +5,7 @@
 use Hoyvoy\CrossDatabase\CanCrossDatabaseShazaamInterface;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Relations\Relation;
+use Illuminate\Support\Str;
 
 trait QueriesRelationships
 {
@@ -34,4 +35,70 @@ protected function addHasWhere(Builder $hasQuery, Relation $relation, $operator,
 
         return parent::addHasWhere($hasQuery, $relation, $operator, $count, $boolean);
     }
+
+    /**
+     * Add subselect queries to count the relations.
+     *
+     * @param mixed $relations
+     *
+     * @return $this
+     */
+    public function withCount($relations)
+    {
+        if (empty($relations)) {
+            return $this;
+        }
+
+        if (is_null($this->query->columns)) {
+            $this->query->select([$this->query->from.'.*']);
+        }
+
+        $relations = is_array($relations) ? $relations : func_get_args();
+
+        foreach ($this->parseWithRelations($relations) as $name => $constraints) {
+            // First we will determine if the name has been aliased using an "as" clause on the name
+            // and if it has we will extract the actual relationship name and the desired name of
+            // the resulting column. This allows multiple counts on the same relationship name.
+            $segments = explode(' ', $name);
+
+            unset($alias);
+
+            if (count($segments) == 3 && Str::lower($segments[1]) == 'as') {
+                list($name, $alias) = [$segments[0], $segments[2]];
+            }
+
+            $relation = $this->getRelationWithoutConstraints($name);
+
+            // Here we will get the relationship count query and prepare to add it to the main query
+            // as a sub-select. First, we'll get the "has" query and use that to get the relation
+            // count query. We will normalize the relation name then append _count as the name.
+            $query = $relation->getRelationExistenceCountQuery(
+                $relation->getRelated()->newQuery(), $this
+            );
+
+            $query->callScope($constraints);
+
+            $query->mergeConstraintsFrom($relation->getQuery());
+
+            // If connection implements CanCrossDatabaseShazaamInterface we must attach database
+            // connection name in from to be used by grammar when query compiled
+            if ($this->getConnection() instanceof CanCrossDatabaseShazaamInterface) {
+                $subqueryConnection = $query->getConnection()->getDatabaseName();
+                $queryConnection = $this->getConnection()->getDatabaseName();
+                if ($queryConnection != $subqueryConnection) {
+                    $queryFrom = $query->getQuery()->from.'<-->'.$subqueryConnection;
+                    $query->from($queryFrom);
+                }
+            }
+
+            // Finally we will add the proper result column alias to the query and run the subselect
+            // statement against the query builder. Then we will return the builder instance back
+            // to the developer for further constraint chaining that needs to take place on it.
+            $column = $alias ?? Str::snake($name.'_count');
+
+            $this->selectSub($query->toBase(), $column);
+        }
+
+        return $this;
+    }
 }

tests/Integration/DatabaseEloquentSubqueriesCrossDatabaseTest.php

@@ -178,6 +178,65 @@ public function testWhereDoesntHaveAcrossDatabaseConnection()
         });
         $this->assertEquals('select * from "users" where not exists (select * from "posts" where "users"."id" = "posts"."user_id" and "name" like ?)', $query->toSql());
     }
+
+    public function testWithCountAcrossDatabaseConnection()
+    {
+        // Test MySQL cross database subquery
+        $query = UserMysql::withCount(['orders' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select `users`.*, (select count(*) from `mysql2`.`orders` where `users`.`id` = `orders`.`user_id` and `name` like ?) as `orders_count` from `users`', $query->toSql());
+
+        // Test MySQL same database subquery
+        $query = UserMysql::withCount(['posts' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select `users`.*, (select count(*) from `posts` where `users`.`id` = `posts`.`user_id` and `name` like ?) as `posts_count` from `users`', $query->toSql());
+
+        // Test PostgreSQL cross database subquery
+        $query = UserPgsql::withCount(['orders' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select "users".*, (select count(*) from "pgsql2"."orders" where "users"."id" = "orders"."user_id" and "name" like ?) as "orders_count" from "users"', $query->toSql());
+
+        // Test PostgreSQL same database subquery
+        $query = UserPgsql::withCount(['posts' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select "users".*, (select count(*) from "posts" where "users"."id" = "posts"."user_id" and "name" like ?) as "posts_count" from "users"', $query->toSql());
+
+        // Test SQL Server cross database subquery
+        $query = UserSqlsrv::withCount(['orders' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select [users].*, (select count(*) from [sqlsrv2].[orders] where [users].[id] = [orders].[user_id] and [name] like ?) as [orders_count] from [users]', $query->toSql());
+
+        // Test SQL Server same database subquery
+        $query = UserSqlsrv::withCount(['posts' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select [users].*, (select count(*) from [posts] where [users].[id] = [posts].[user_id] and [name] like ?) as [posts_count] from [users]', $query->toSql());
+
+        // Test SQL Server cross database subquery
+        $query = UserSqlite::withCount(['orders' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select "users".*, (select count(*) from "orders" where "users"."id" = "orders"."user_id" and "name" like ?) as "orders_count" from "users"', $query->toSql());
+
+        // Test SQL Server same database subquery
+        $query = UserSqlite::withCount(['posts' => function ($query) {
+                $query->where('name', 'like', '%a%');
+            }
+        ]);
+        $this->assertEquals('select "users".*, (select count(*) from "posts" where "users"."id" = "posts"."user_id" and "name" like ?) as "posts_count" from "users"', $query->toSql());
+    }
 }
 
 class UserMysql extends Model