WITH在MYSQL中的用法示例详解

WITH cte_name AS (
    SELECT ...  -- 定义CTE的查询
)
SELECT ... FROM cte_name;  -- 主查询使用CTE

WITH sales_summary AS (
    SELECT product_id, SUM(quantity) AS total_sold
    FROM orders
    GROUP BY product_id
)
SELECT p.product_name, s.total_sold
FROM products p
JOIN sales_summary s ON p.product_id = s.product_id;

WITH 
customer_orders AS (
    SELECT customer_id, COUNT(*) AS order_count
    FROM orders
    GROUP BY customer_id
),
high_value_customers AS (
    SELECT customer_id
    FROM customer_orders
    WHERE order_count > 5
)
SELECT c.customer_name
FROM customers c
JOIN high_value_customers h ON c.customer_id = h.customer_id;

WITH RECURSIVE org_hierarchy AS (
    -- 基础查询（锚成员）
    SELECT id, name, parent_id, 1 AS level
    FROM organization
    WHERE parent_id IS NULL
    UNION ALL
    -- 递归查询（递归成员）
    SELECT o.id, o.name, o.parent_id, h.level + 1
    FROM organization o
    JOIN org_hierarchy h ON o.parent_id = h.id
)
SELECT * FROM org_hierarchy;

-- 不使用CTE（重复子查询）
SELECT * FROM (SELECT ... FROM table1) AS t1
JOIN (SELECT ... FROM table1) AS t2...
-- 使用CTE（避免重复）
WITH t1 AS (SELECT ... FROM table1)
SELECT * FROM t1 JOIN t1 AS t2...

WITH 
monthly_sales AS (...),
product_ranking AS (...)
SELECT ... FROM monthly_sales JOIN product_ranking...

WITH 
raw_data AS (...),
cleaned_data AS (...),
enriched_data AS (...)
SELECT * FROM enriched_data;

WITH RECURSIVE comment_tree AS (...)
SELECT * FROM comment_tree;

WITH cte_name AS (
    SELECT /*+ MATERIALIZE */ ...  -- 强制物化
)

WITH cte_name AS (
    SELECT /*+ MERGE */ ...  -- 强制合并到主查询
)

SET @@cte_max_recursion_depth = 2000;