Question

我收到了以下问题：

SELECT      SQL_CALC_FOUND_ROWS u.unit_id, u.unit_serial_full, u.unit_status, u.contract_id, u.warehouse_id,
            m.model_name,
            c.contract_name,
            t.transfer_id,
            w.warehouse_name_full
FROM        units AS u
LEFT JOIN   models AS m ON m.model_id = u.model_id
LEFT JOIN   contracts AS c ON c.contract_id = u.contract_id
LEFT JOIN   transfers AS t ON t.transfer_id = u.transfer_id
LEFT JOIN   warehouses AS w ON w.warehouse_id = u.warehouse_id
LEFT JOIN   units_attributes AS ua ON ua.unit_id = u.unit_id
WHERE       1
        AND u.company_id = :company_id
        AND (
                (
                    u.model_id = "4"
                AND (
                        ua.attribute_id = :attribute_id_0 AND attribute_default = :attribute_value_0
                    )
                AND (
                        ua.attribute_id = :attribute_id_1 AND attribute_default = :attribute_value_1
                    )
                )
            )

如果我使用2个或更多属性进行搜索，则不会产生任何结果，但如果我只有1个属性，则查询会按预期工作。有什么想法吗？

搜索必须严格。不是用通配符。

感谢。

Answer 1

嗯，ua.attribute_id不能同时是两个值

(
    ua.attribute_id = :attribute_id_0 AND attribute_default = :attribute_value_0
)
AND (
    ua.attribute_id = :attribute_id_1 AND attribute_default = :attribute_value_1
)

Answer 2

SELECT      SQL_CALC_FOUND_ROWS u.unit_id, u.unit_serial_full, u.unit_status, u.contract_id, u.warehouse_id, m.model_name, c.contract_name, t.transfer_id, w.warehouse_name_full
FROM        units AS u
LEFT JOIN   models AS m ON m.model_id = u.model_id
LEFT JOIN   contracts AS c ON c.contract_id = u.contract_id
LEFT JOIN   transfers AS t ON t.transfer_id = u.transfer_id
LEFT JOIN   warehouses AS w ON w.warehouse_id = u.warehouse_id
LEFT JOIN   units_attributes AS ua ON ua.unit_id = u.unit_id
WHERE 1 = 1
    AND u.company_id = :company_id
    AND u.model_id = "4"
    AND ua.attribute_id IN (:attribute_id_0, :attribute_id_1)
    AND attribute_default IN (:attribute_value_0, :attribute_value_1)

Answer 3

列不能同时具有两个不同的值。因此，ua.attribute_id = :foo AND ua.attribute_id = :bar等过滤器会生成Impossible WHERE子句。

最佳解决方案通常是分组您的结果，并仅为包含符合条件的记录的结果组过滤结果组，即使用HAVING子句：

GROUP BY col1, col2, col3
HAVING   SUM(ua.attribute_id = :foo) AND SUM(ua.attribute_id = :bar)

MySQL属性搜索（严格）

3 个答案: