[英]Select Categories and count the Ads inside
我要查询一个选择类别名称并计算每个类别中活动广告的最大数量的查询,我已经这样做了:
SELECT
cat.cat_id,
cat.cat_desc,
COUNT(ad_id) AS cat_total_ads
FROM
tab_categories AS cat LEFT JOIN
tab_ads AS ads ON ads.cat_id = cat.cat_id
WHERE
cat_active = @cat_active AND
cat_deleted = @cat_deleted
GROUP BY
cat_desc, cat.cat_id
该查询也在计算无效广告。 如何将无效广告的值设为0?
SUM(CASE .....然后1 else 0 end)作为colName应该为你做!
尝试此操作,我没有要重新创建的表以进行测试,但是此操作或类似操作应该起作用。
select
cat.cat_id,
cat.cat_desc,
count(ad_id) as Total,
sum(case when ad_id= 0 then 1 else 0 end) as 'ad_id'
from
tab_categoriesAS cat LEFT JOIN
tab_ads AS ads ON ads.cat_id = cat.cat_id
WHERE
cat_active = @cat_active AND
cat_deleted = @cat_deleted
GROUP BY
cat_desc, cat.cat_id
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