fix: invalid filter

Author: Ruben Nogueira

lib/sql.js

@@ -1125,17 +1125,19 @@ SQLConnector.prototype._buildWhere = function(model, where) {
       if (Array.isArray(clauses)) {
         for (let i = 0, n = clauses.length; i < n; i++) {
           const stmtForClause = self._buildWhere(model, clauses[i]);
-          if (stmtForClause.sql) {
+          if (stmtForClause.sql) { // first case, getting into ()
             stmtForClause.sql = '(' + stmtForClause.sql + ')';
             branchParams = branchParams.concat(stmtForClause.params);
             branches.push(stmtForClause.sql);
           }
         }
-        stmt.merge({
-          sql: '(' + branches.join(' ' + key.toUpperCase() + ' ') + ')',
-          params: branchParams,
-        });
-        whereStmts.push(stmt);
+        if (branches.length > 0) {
+          stmt.merge({
+            sql: '(' + branches.join(' ' + key.toUpperCase() + ' ') + ')',
+            params: branchParams,
+          });
+          whereStmts.push(stmt);
+        }
         continue;
       }
       // The value is not an array, fall back to regular fields