Question

我想从MySQL读取一行内容，该行内容提供了我的平均值，std dev pop和max以及mins。

基本上，我想从特定的表中获得MIN，但不是0，或者小于0。

我尝试过

MIN(NULLIF(`stock_qty`, 0)) AS `stock_qty`,

作为SELECT参数，但是如果MIN为0，则仅返回null

我当前的方法如下：

SELECT 
    MAX(`stock_qty`) AS `stock_qty_max`,
    MIN(`stock_qty`) AS `stock_qty_min`,
    AVG(`stock_qty`) AS `stock_qty_avg`,
    STDDEV_POP(`stock_qty`) AS `stock_qty_std`,
    SUM(`stock_qty`) AS `stock_qty_sum`,
    MAX(`adjusted_online_set`) AS `adjusted_online_set_max`,
    MIN(`adjusted_online_set`) AS `adjusted_online_set_min`,
    AVG(`adjusted_online_set`) AS `adjusted_online_set_avg`,
    STDDEV_POP(`adjusted_online_set`) AS `adjusted_online_set_std`,
    SUM(`adjusted_online_set`) AS `adjusted_online_set_sum`,
    COUNT(*) AS `count`
FROM
    `cat_product` AS `prod`
        LEFT JOIN
    `cat_position` AS `pos` ON pos.product_id = prod.product_id
        RIGHT JOIN
    `cat_product_website` AS `pweb` ON pos.product_id = pweb.product_id
WHERE
    (pos.category_id = '8476')
    AND ((prod.adjusted_online_set > 0) OR (prod.stock_qty > 0))

但是，这两个字段也都返回负值。

Answer 1

min（案件当stock_qty> 0时stock_qty 否则为空结束）AS stock_qty

查找MIN值> 0，也没有负值

1 个答案: