Question

我试图仅在没有包含两个值的现有记录时才将记录插入表中。此查询抛出错误：＆＃34;语法在＆＃39; WHERE NOT EXISTS＆＃34;

附近使用

我已尝试过SO帖子中的各种示例，但似乎无法实现这一目标。

INSERT INTO tasks_admin2agent 
(trans_id,category,task_name,task_detail,date_due_d) 
VALUES 
('2186597-L1','Listing','Incomplete Listing Record', 'Please complete the 
listing record','2018-03-31') 
WHERE NOT EXISTS 
   (SELECT 
    trans_id,task_name 
    FROM tasks_admin2agent 
    WHERE trans_id = '2186597-L1' 
    AND task_name = 'Incomplete Listing Record'
    )

Answer 1

对我而言，如果你改变＆＃34; VALUES＆＃34;到＆＃34; SELECT＆＃34;。但我无法解释为什么会这样做

INSERT INTO tasks_admin2agent 
(trans_id,category,task_name,task_detail,date_due_d) 
SELECT 
('2186597-L1','Listing','Incomplete Listing Record', 'Please complete the 
listing record','2018-03-31') FROM tasks_admin2agent
WHERE NOT EXISTS 
   (SELECT 
    trans_id,task_name 
    FROM tasks_admin2agent 
    WHERE trans_id = '2186597-L1' 
    AND task_name = 'Incomplete Listing Record'
    )

Answer 2

试试这个：

INSERT INTO tasks_admin2agent 
(trans_id,category,task_name,task_detail,date_due_d) 
SELECT 
'2186597-L1','Listing','Incomplete Listing Record', 'Please complete the 
listing record','2018-03-31' from tasks_admin2agent
WHERE NOT EXISTS 
(SELECT 
 *
FROM tasks_admin2agent 
WHERE trans_id = '2186597-L1' 
AND task_name = 'Incomplete Listing Record'
);

您还可以查看： INSERT VALUES WHERE NOT EXISTS

Answer 3

尝试类似

的内容

INSERT INTO tasks_admin2agent 
(trans_id,category,task_name,task_detail,date_due_d) 
SELECT 
'2186597-L1','Listing','Incomplete Listing Record', 'Please complete the 
listing record','2018-03-31' FROM tasks_admin2agent
WHERE NOT EXISTS 
   (SELECT 
    *
    FROM tasks_admin2agent 
    WHERE trans_id = '2186597-L1' 
    AND task_name = 'Incomplete Listing Record'
    );

您可以尝试Demo

Answer 4

只需在相关的两列上设置（Composite-）Key-Constraint（唯一）：

ALTER TABLE tbl ADD UNIQUE KEY `uniqueConstraint` (col1, col2);

使用常规插入物和＆＃34;手柄＆＃34; ＆＃34;重复关键错误＆＃34; - ＆GT;这意味着价值对已经存在。

这也允许您将查询与ON DUPLICATE KEY UPDATE - 语法结合使用。（如果需要）

请注意，中止的插入或On duplicate key update无论如何都会消耗下一个自动增量ID。

Answer 5

能够使用FROM DUAL从此示例中获得它。

谢谢大家的帮助！

How to 'insert if not exists' in MySQL?

minimize_scalar

如果MYSQL中不存在两个值，则插入记录（同一个表）

5 个答案: