如何使用此功能显示计数?

因此,这会生成21行数据,但我希望它显示实际计数为21。有什么想法/建议吗?

SELECT * FROM PRODUCT left join VENDOR ON PRODUCT.V_CODE = VENDOR.V_CODE 
UNION
SELECT * FROM PRODUCT RIGHT JOIN VENDOR ON PRODUCT.V_CODE = VENDOR.V_CODE;
uwycny 回答:如何使用此功能显示计数?

您可以对每次选择的计数求和。

SELECT SUM(c) FROM (
SELECT COUNT(*) as c FROM PRODUCT left join VENDOR ON PRODUCT.V_CODE = VENDOR.V_CODE 
UNION
SELECT COUNT(*) FROM PRODUCT RIGHT JOIN VENDOR ON PRODUCT.V_CODE = VENDOR.V_CODE;
);
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