摘要：
一、分组数据 数据分组1 mysql> SELECT COUNT(*) AS num_prods2 -> FROM products3 -> WHERE vend_id = 1003;4 +-----------+5 | num_prods |6 +-----------+7 | 7 |8 +-----------+9 1 row in set (0.03 sec) 创建分组 1 mysql> SELECT vend_id, COUNT(*) AS num_prods 2 -> FROM products 3 -> GROUP BY vend... 阅读全文
