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我正在尝试模拟完整的外部联接，将两个表相互比较。batch_import 表包含需要插入的记录，前提是它们不存在于employees 表中。为此，我尝试了以下查询：

INSERT INTO employees (forename, surname, employersId, custom_corpore_headOffice, contractId)
SELECT firstname, surname, employeenumber, dob, store, contractId
FROM batch_import
LEFT JOIN employees ON batch_import.employeenumber = employees.employersId AND batch_import.contractId = employees.contractId
UNION ALL
SELECT forename, surname, employersId, custom_corpore_headOffice, contractId
FROM batch_import RIGHT JOIN employees ON batch_import.employeenumber = employees.employersId AND batch_import.contractId = employees.contractId
WHERE batch_import.employeenumber IS NULL AND batch_import.contractId IS NULL
                       ";

但是，当我运行此查询时，我从 mysql 收到消息：错误 1137（HY000）：无法重新打开表：'batch_import'

我猜这是我的 UNION ALL 的逻辑不正确。有人可以帮我找到解决方案吗？

编辑:: 我已经尝试过这个查询，它一直在表中添加记录，从最后一条记录开始。我也试过：

                    INSERT INTO employees (forename, surname, employersId, dateOfBirth, custom_corpore_headOffice, contractId)
                SELECT firstname, batch_import.surname, employeenumber, dob, store, batch_import.contractId
                FROM batch_import
                LEFT JOIN employees ON batch_import.employeenumber = employees.employersId AND batch_import.contractId = employees.contractId
                UNION
                SELECT firstname, batch_import.surname, employeenumber, dob, store, batch_import.contractId
                FROM batch_import RIGHT JOIN employees ON batch_import.employeenumber = employees.employersId AND batch_import.contractId = employees.contractId;

但仍然无济于事。它不会忽略存在的内容，而是将所有内容都写入表的末尾。

也试过：INSERT INTO employees (forename, surname, employersId, dateOfBirth, custom_corpore_headOffice, contractId) SELECT firstname, batch_import.surname, employeenumber, dob, store, batch_import.contractId FROM batch_import LEFT JOIN employees ON employees.employersId = NULL;

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1 回答 1

1

选项1

INSERT INTO employees (forename, surname, employersId, custom_corpore_headOffice, contractId)
SELECT firstname, surname, employeenumber, dob, store, contractId
FROM batch_import
WHERE NOT EXISTS (Select 1 From employees where batch_import.employeenumber = employees.employersId AND batch_import.contractId = employees.contractId)

选项 2

INSERT INTO employees (forename, surname, employersId, custom_corpore_headOffice, contractId)
SELECT firstname, surname, employeenumber, dob, store, contractId
FROM batch_import
LEFT JOIN employees ON batch_import.employeenumber = employees.employersId AND batch_import.contractId = employees.contractId
WHERE employees.employersId is NULL
于 2015-01-07T14:35:54.533 回答