MySQL JOIN与LEFT JOIN的差异

Question

我有一个跨数据库的查询...

SELECT
            `DM_Server`.`Jobs`.*,
            `DM_Server`.servers.Description AS server,
            digital_inventory.params,
            products.products_id,
            products.products_pdfupload,
            customers.customers_firstname,
            customers.customers_lastname
        FROM `DM_Server`.`Jobs`
        INNER JOIN `DM_Server`.servers ON servers.ServerID = Jobs.Jobs_ServerID
        JOIN `cpod_live`.`digital_inventory` ON digital_inventory.jobname = Jobs.Jobs_Name
        JOIN `cpod_live`.`products` ON products.products_pdfupload = CONCAT(digital_inventory.jobname, ".pdf")
        JOIN `cpod_live`.`customers` ON customers.customers_id = products.cID
        ORDER BY `DM_Server`.`Jobs`.Jobs_StartTime DESC LIMIT 50

它运行得很好，直到我将它们设置为LEFT JOINs。我想，如果没有指定连接类型，它就会被假定为LEFT JOIN。难道不是这样吗？

Answer 1

不是的。如果未指定类型，则使用INNER JOIN。阅读不同之处；wikipedia

Answer 2

如果只指定JOIN，我相信缺省值是INNER JOIN。