Question

我的数据库中有一个appraisal_lines表，想要从第一次评估中获取一些数据，并将其与最新评估中的相同数据一起显示，这样可以很容易地看到从第一次评估到当前评估的进展。我使用来自评估的三个值加上当前评估的其他数据来做这个。

要做到这一点，我想我需要创建临时表来保存两组字段以及当前评估中的其他字段。

我的临时表创建如下：

CREATE TEMPORARY TABLE appraisal_lines_submitted (
    current_perceived_state INT(2),
    current_actual_state INT(2),
    current_desired_state INT(2),
    agreed_action_points TEXT,
    agreed_actions_target_date DATE,
    assessor_notes TEXT,
    category_id INT(2),
    sub_categories_id INT(2),
    sub_categories_description VARCHAR(45),
    sequence_number INT(3) PRIMARY KEY,
    first_perceived_state INT(2),
    first_actual_state INT(2),
    first_desired_state INT(2)
);

然后我按如下方式运行insert和select语句，将当前评估中的数据放入临时表中：

INSERT INTO appraisal_lines_submitted (
    current_perceived_state,
    current_actual_state,
    current_desired_state,
    agreed_action_points,
    agreed_actions_target_date,
    assessor_notes,
    category_id,
    sub_categories_id,
    sub_categories_description,
    sequence_number)
SELECT appraisal_lines.perceived_state,
    appraisal_lines.actual_state,
    appraisal_lines.desired_state,
    appraisal_lines.agreed_action_points,
    DATE_FORMAT (appraisal_lines.agreed_actions_target_date, '%d/%m/%Y') AS agreed_actions_target_date_formatted,
    appraisal_lines.assessor_notes,
    appraisal_lines.assessment_category_id,
    assessment_sub_categories.id,
    assessment_sub_categories.description,
    assessment_sub_categories.sequence_number
FROM appraisal_lines LEFT JOIN assessment_sub_categories
    ON appraisal_lines.assessment_sub_category_id = assessment_sub_categories.id
WHERE hyperlink_token ='db678f8595edcd78d8ea7f055f7ee790b804c91e'
    AND assessment_category_id ='5'
ORDER BY sequence_number;

这样可以。

但是，当我运行下面的更新语句时，它失败了

UPDATE appraisal_lines_submitted JOIN
    (SELECT appraisal_lines.perceived_state as update_perceived_state
     FROM appraisal_lines
     WHERE hyperlink_token ='d7cc7e1adc116e0dac31cbad34cd9a2b322c3507'
        AND assessment_category_id ='5'
     ORDER BY appraisal_lines.assessment_sub_category_id
    ) AS increments 
    ON increments.update_perceived_state = appraisal_lines.perceived_state
    SET appraisal_lines_submitted.first_perceived_state = update_perceived_state;

错误

错误代码：1054
'on clause'
中的未知列'appraisal_lines.perceived_state'

我根据帖子MySQL Update a field value with subquery with multiple returning rows

撰写了更新声明

Answer 1

这是你的脚本，其中一些位用粗体突出显示：

UPDATE appraisal_lines_submitted JOIN
    (SELECT appraisal_lines.perceived_state as update_perceived_state
     FROM appraisal_lines
     WHERE hyperlink_token ='d7cc7e1adc116e0dac31cbad34cd9a2b322c3507'
        AND assessment_category_id ='5'
     ORDER BY appraisal_lines.assessment_sub_category_id
    ) AS increments 
    ON increments.update_perceived_state = appraisal_lines.perceived_state
    SET appraisal_lines_submitted.first_perceived_state = update_perceived_state;

现在，在您的脚本中，您将一个名为appraisal_lines_submitted的表连接到名为increments的（派生）表。加入条件引用increments中的列和...中的列...等一下，appraisal_lines？那是什么？参加联合的人中没有该名称的表格。

我的猜测是，加入条件中的appraisal_lines.perceived_state引用应替换为appraisal_lines_submitted.current_perceived_state。

我的另一个猜测是，您在LIMIT 1之后错过了ORDER BY，这是基于要更新的列的名称（first_perceived_state）

Answer 2

解析器无法查看表appraisal_lines，因为您正在更新appraisal_lines_submitted。

您在内部appraisal_lines内指定SELECT的唯一位置，其别名为increments

您也可以将ORDER BY放在内部SELECT中，无论内部数据的排序如何，都会执行连接。

使用子查询和联接表的UPDATE临时表失败

2 个答案: