分組數據

1 介紹 分組返回數據，不是where的那種返回特定數據web 2 建立分組(group by) select vend_id, count(*) as num_prods from products group by vend_id; 2.1 分析 按vend_id字段分組，而後統計總數返回數據sql 3 過濾分組(having) select cust_id, count(*) as orde

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