group concat查询的查询优化

Question

我有以下数据库架构 -

shop_orders(id, project_id, selling_price, tax_amount, ...)

project_contacts(id, project_id, contact_id, ...)

projects(project_id, project_contact_id, site_contact_id, ...)

样本数据 -

shop_orders(1, 123456, 24.35, 2.34, ...)
project_contacts(1, 123456, 10001, ...)
projects(123456, 10001, 10002, ...)

期望的输出 -

123456:26.69

我正在尝试执行以下查询 -

SELECT GROUP_CONCAT(CONCAT(project_id, ':', (`selling_price` + `tax_amount`))) AS project_amount 
FROM shop_orders 
WHERE project_id IN (
   SELECT project_id FROM project_contacts WHERE contact_id=10001 
   UNION SELECT project_id FROM projects WHERE project_contact_id=10001 
   UNION SELECT project_id FROM projects WHERE site_contact_id=10001 
)

此查询在项目表大小约为 800 的演示服务器中运行良好，而在生产服务器中不起作用 [即它只是继续在僵尸状态下运行，] 项目表大小约为 9000。

请让我知道优化查询的任何指示。

编辑

即使这个查询也没有返回任何响应 -

SELECT CONCAT(project_id, ':', (`selling_price` + `tax_amount`)) AS project_amount 
FROM shop_orders 
WHERE project_id IN (
  SELECT project_id FROM project_contacts WHERE contact_id=10001 
  UNION SELECT project_id FROM projects WHERE project_contact_id=10001 
  UNION SELECT project_id FROM projects WHERE site_contact_id=10001
)

虽然如果我运行类似的查询 -

SELECT CONCAT(project_id, ':', (`selling_price` + `tax_amount`)) AS project_amount 
FROM shop_orders WHERE project_id IN (NULL)

它会立即返回答案。另一个联合查询也单独运行得很好。我可以分别运行这两个查询，但不确定为什么单个查询不返回输出。

Answer 1

我将首先使用EXISTS 来表达查询：

SELECT GROUP_CONCAT(CONCAT(project_id, ':', (`selling_price` + `tax_amount`))) AS project_amount 
FROM shop_orders so
WHERE EXISTS (SELECT 1
              FROM project_contacts pc
              WHERE pc.project_id = so.project_id AND
                    pc.contact_id = 10001
             ) OR
      EXISTS (SELECT 1
              FROM project p
              WHERE p.project_id = so.project_id AND
                    p.project_contact_id = 10001
             ) OR
      EXISTS (SELECT 1
              FROM project p
              WHERE p.project_id = so.project_id AND
                    p.site_contact_id = 10001
             );

为了获得最佳性能，您需要以下索引：

• project_contacts(project_id, contact_id)
• project(project_id, projecct_contact_id)
• project(project_id, site_contact_id)

我应该注意到CONCAT() 在GROUP_CONCAT() 中是多余的，因为它需要多个参数：

SELECT GROUP_CONCAT(project_id, ':', (`selling_price` + `tax_amount`)) AS project_amount