[7.1、count](7.1%E3%80%81count.md) [7.2、sum](7.2%E3%80%81sum.md) [7.3、avg](7.3%E3%80%81avg.md) [7.4、max](7.4%E3%80%81max.md) [7.5、min](7.5%E3%80%81min.md) [7.6、组合聚合函数](7.6%E3%80%81%E7%BB%84%E5%90%88%E8%81%9A%E5%90%88%E5%87%BD%E6%95%B0.md) [7.7 函数总结(了解内容)](7.7%E5%87%BD%E6%95%B0%E6%80%BB%E7%BB%93.md)