diff --git a/src/Eloquent/Builder.php b/src/Eloquent/Builder.php
index f34cda5..f5294c8 100644
--- a/src/Eloquent/Builder.php
+++ b/src/Eloquent/Builder.php
@@ -11,5 +11,6 @@ class Builder extends IlluminateEloquentBuilder
     use IlluminateEloquentQueriesRelationships, CrossDatabaseQueriesRelationships {
         CrossDatabaseQueriesRelationships::addHasWhere insteadof IlluminateEloquentQueriesRelationships;
         CrossDatabaseQueriesRelationships::withCount insteadof IlluminateEloquentQueriesRelationships;
+        CrossDatabaseQueriesRelationships::has insteadof IlluminateEloquentQueriesRelationships;
     }
 }
diff --git a/src/Eloquent/Concerns/QueriesRelationships.php b/src/Eloquent/Concerns/QueriesRelationships.php
index a94f304..a80d9fc 100644
--- a/src/Eloquent/Concerns/QueriesRelationships.php
+++ b/src/Eloquent/Concerns/QueriesRelationships.php
@@ -2,21 +2,132 @@
 
 namespace Hoyvoy\CrossDatabase\Eloquent\Concerns;
 
+use Closure;
 use Hoyvoy\CrossDatabase\CanCrossDatabaseShazaamInterface;
+use Illuminate\Database\ConnectionInterface;
 use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
 use Illuminate\Database\Eloquent\Relations\Relation;
+use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
+use RuntimeException;
 
 trait QueriesRelationships
 {
+
+    /**
+     * Add a relationship count / exists condition to the query.
+     *
+     * @param \Illuminate\Database\Eloquent\Relations\Relation|string $relation
+     * @param string $operator
+     * @param int $count
+     * @param string $boolean
+     * @param \Closure|null $callback
+     * @return \Illuminate\Database\Eloquent\Builder|\Illuminate\Database\Eloquent\Concerns\QueriesRelationships
+     *
+     * @throws \RuntimeException
+     */
+    public function has($relation, $operator = '>=', $count = 1, $boolean = 'and', Closure $callback = null)
+    {
+        if (is_string($relation)) {
+            if (strpos($relation, '.') !== false) {
+                return $this->hasNested($relation, $operator, $count, $boolean, $callback);
+            }
+
+            $relation = $this->getRelationWithoutConstraints($relation);
+        }
+
+        if ($relation instanceof MorphTo) {
+            throw new RuntimeException('Please use whereHasMorph() for MorphTo relationships.');
+        }
+
+
+        // If we only need to check for the existence of the relation, then we can optimize
+        // the subquery to only run a "where exists" clause instead of this full "count"
+        // clause. This will make these queries run much faster compared with a count.
+        $method = $this->canUseExistsForExistenceCheck($operator, $count)
+            ? 'getRelationExistenceQuery'
+            : 'getRelationExistenceCountQuery';
+
+        $hasQuery = $relation->{$method}(
+            $relation->getRelated()->newQueryWithoutRelationships(), $this
+        );
+
+
+        // Next we will call any given callback as an "anonymous" scope so they can get the
+        // proper logical grouping of the where clauses if needed by this Eloquent query
+        // builder. Then, we will be ready to finalize and return this query instance.
+        if ($callback) {
+            $hasQuery->callScope($callback);
+        }
+
+        if (!$this->isSameHost($relation->getConnection())) {
+            // Subquery is not possible. Do a workaround in stead:
+            if ($relation instanceof BelongsTo) {
+                // 1. Execute a separate query to obtain ids of related models.
+                // 2. Use these ids in a standard where clause on the foreign key.
+                // First modify hasQuery and execute it to get the owner ids.
+                /** @var \Illuminate\Database\Query\Builder $remoteQuery */
+                $remoteQuery = $hasQuery->getQuery();
+                // Remove the where clause joining the two tables
+                $linkClause = [
+                    'type' => 'Column',
+                    'first' => $relation->getQualifiedForeignKeyName(),
+                    'operator' => '=',
+                    'second' => $relation->getQualifiedOwnerKeyName(),
+                    'boolean' => 'and'
+                ];
+                foreach ($remoteQuery->wheres as $i => $where) {
+                    if ($where === $linkClause) {
+                        unset($remoteQuery->wheres[$i]);
+                        break;
+                    }
+                }
+                // Obtain matching owner ids
+                $ids = $remoteQuery->pluck('id');
+                // Return the constrained query
+                if ($operator === '<') {
+                    return $this->where(function ($clause) use ($relation, $ids) {
+                        $clause->whereNotIn($relation->getForeignKeyName(), $ids);
+                        $clause->orWhereNull($relation->getForeignKeyName());
+                    });
+                }
+                return $this->whereIn($relation->getForeignKeyName(), $ids);
+            }
+        }
+
+        return $this->addHasWhere(
+            $hasQuery, $relation, $operator, $count, $boolean
+        );
+    }
+
+    /**
+     * @return bool
+     */
+    protected function isSameHost(ConnectionInterface $connection)
+    {
+        $ownConfig = Arr::only($this->getConnection()->getConfig(), [
+            'driver',
+            'host',
+            'port'
+        ]);
+        $otherConfig = Arr::only($connection->getConfig(), [
+            'driver',
+            'host',
+            'port'
+        ]);
+        return $ownConfig === $otherConfig;
+    }
+
     /**
      * Add the "has" condition where clause to the query.
      *
-     * @param \Illuminate\Database\Eloquent\Builder            $hasQuery
+     * @param \Illuminate\Database\Eloquent\Builder $hasQuery
      * @param \Illuminate\Database\Eloquent\Relations\Relation $relation
-     * @param string                                           $operator
-     * @param int                                              $count
-     * @param string                                           $boolean
+     * @param string $operator
+     * @param int $count
+     * @param string $boolean
      *
      * @return \Illuminate\Database\Eloquent\Builder|static
      */
@@ -27,8 +138,8 @@ protected function addHasWhere(Builder $hasQuery, Relation $relation, $operator,
         if ($this->getConnection() instanceof CanCrossDatabaseShazaamInterface) {
             $subqueryConnection = $hasQuery->getConnection()->getDatabaseName();
             $queryConnection = $this->getConnection()->getDatabaseName();
-            if ($queryConnection != $subqueryConnection) {
-                $queryFrom = $hasQuery->getConnection()->getTablePrefix().'<-->'.$hasQuery->getQuery()->from.'<-->'.$subqueryConnection;
+            if ($queryConnection !== $subqueryConnection) {
+                $queryFrom = $hasQuery->getConnection()->getTablePrefix() . '<-->' . $hasQuery->getQuery()->from . '<-->' . $subqueryConnection;
                 $hasQuery->from($queryFrom);
             }
         }
@@ -50,7 +161,7 @@ public function withCount($relations)
         }
 
         if (is_null($this->query->columns)) {
-            $this->query->select([$this->query->from.'.*']);
+            $this->query->select([$this->query->from . '.*']);
         }
 
         $relations = is_array($relations) ? $relations : func_get_args();
@@ -84,7 +195,7 @@ public function withCount($relations)
                 $subqueryConnection = $query->getConnection()->getDatabaseName();
                 $queryConnection = $this->getConnection()->getDatabaseName();
                 if ($queryConnection != $subqueryConnection) {
-                    $queryFrom = $query->getConnection()->getTablePrefix().'<-->'.$query->getQuery()->from.'<-->'.$subqueryConnection;
+                    $queryFrom = $query->getConnection()->getTablePrefix() . '<-->' . $query->getQuery()->from . '<-->' . $subqueryConnection;
                     $query->from($queryFrom);
                 }
             }
@@ -98,11 +209,16 @@ public function withCount($relations)
             // 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');
+            $column = $alias ?? Str::snake($name . '_count');
 
             $this->selectSub($query, $column);
         }
 
         return $this;
     }
+
+    protected function generateCrossHostQuery(Relation $relation)
+    {
+
+    }
 }