Modern database systems rely on workload forecasting to guide performance tuning, resource allocation, and query optimization. However, evolving query patterns and resource demands make accurate workload forecasting increasingly challenging. Most existing methods separately model query and resource behaviors using simple statistics or single-scale forecasting models, thereby ignoring their inherent correlations and leading to inaccurate modeling of real-world workload behaviors. In practice, real-world workloads show that query and resource behaviors are often interdependent and exhibit temporal dynamics. However, most forecasting methods overlook the inherent correlations between query and resource, as well as the temporal patterns across multi-scale resolutions in real workloads. To address these issues, we propose QuadraFormer, an end-to-end forecasting framework that jointly predicts query and resource usage. First, we introduce a unified workload representation that integrates query and resource information into a structured input, enabling joint modeling of workload across variates. Second, we develop an adaptive multi-scale routing mechanism that selects appropriate temporal resolutions to capture periodic patterns and multi-scale variability. Third, we design a novel Quadra-attention mechanism that models both intra- and inter-patch temporal dependencies as well as intra- and inter-dimensional dependencies. Extensive experiments on real-world workloads show that QuadraFormer consistently outperforms competitive baselines, achieving the highest F1 score of 98.38% and accuracy of 86.17%, with F1 improvements of up to 10.28% over the best-performing baseline, while reducing training time by up to 2.16×.