Question

有人可以帮我优化这个查询吗？我可以添加一些索引，只从修改后的（CURRENT_TIMESTAMP）字段中获取日期？

由于杰里米

SELECT a.providerName AS Assureur, b.insuranceType AS Produit, c.votedFor, c.votedFor2, c.email, c.comment, c.modified
FROM insuranceproviders AS a, insurancetypes AS b, insurancevotes AS c
WHERE a.id = c.providerId
AND b.id = c.insTypeId

Answer 1

以下联接查询看起来更好：

SELECT a.providerName AS Assureur, b.insuranceType AS Produit,
    c.votedFor, c.votedFor2, c.email, c.comment, c.modified
FROM insuranceproviders AS a
    INNER JOIN insurancetypes AS b ON a.id = c.providerID
    INNER JOIN  insurancevotes AS c ON b.id = c.insTypeId

并且您应该添加以下INDEX：

ALTER TABLE insuranceproviders ADD INDEX(id);
ALTER TABLE insurancetypes ADD INDEX (providerID, insTypeId);
ALTER TABLE insurancevotes ADD INDEX(insTypeId);

Answer 2

您可以尝试以下方法：
[这里我正在做左连接，因为我不知道表结构，而你也可以有内连接]

SELECT a.providerName AS Assureur, b.insuranceType AS Produit, c.votedFor, c.votedFor2, c.email, c.comment, c.modified
FROM insurancevotes AS c
LEFT JOIN insuranceproviders AS a ON   a.id = c.providerId
LEFT JOIN insurancetypes AS b ON b.id = c.insTypeId

Answer 3

使用a.id，c.providerId，b.id，c.id（如果有）的索引，c.insTypeId

我该如何优化这个mysql查询？

3 个答案: