Question

我有以下sql查询，只有在表

中不存在时才会插入

INSERT INTO message_log (message, from_id, to_id, match_id, unix_timestamp, own_account) VALUES('hi', 'tom', 'tom', '55640ec48a2aecab0e3c096c556f5435f4bb054c68930040', 33333, TRUE)
WHERE NOT EXISTS (SELECT 1 FROM message_log WHERE message = 'hi' AND from_id = 'tom' AND to_id = 'tom' AND match_id = '55640ec48a2aecab0e3c096c556f5435f4bb054c68930040' AND unix_timestamp = 33333)

但是我收到以下错误

ERROR:  syntax error at or near "WHERE"
LINE 2: WHERE NOT EXISTS (SELECT 1 FROM message_log where message = ...
        ^

我做错了什么？

Answer 1

仅当该记录不存在时，才在表中插入记录：

 INSERT INTO message_log (message, from_id, to_id, match_id, unix_timestamp, own_account) 
 SELECT 'hi', 'tom', 'tom', '55640ec48a2aecab0e3c096c556f5435f4bb054c68930040', 33333, TRUE
 FROM message_log
 WHERE NOT EXISTS (SELECT 1 FROM message_log WHERE message = 'hi' AND from_id = 'tom' AND to_id = 'tom' AND match_id = '55640ec48a2aecab0e3c096c556f5435f4bb054c68930040' AND unix_timestamp = 33333)

它有点冗长，但它应该做你想要的。或者，您可以在表上设置唯一的主键，因此如果您尝试插入重复键，数据库将为您提供击键。一个中的六个，另一个中的六个。

Answer 2

以下内容应该

INSERT INTO message_log (message, from_id, to_id, match_id, unix_timestamp, own_account)
SELECT 'hi', 'tom', 'tom', '55640ec48a2aecab0e3c096c556f5435f4bb054c68930040', 33333, TRUE
WHERE NOT EXISTS (SELECT 1 FROM message_log WHERE message = 'hi' AND from_id = 'tom'
    AND to_id = 'tom' AND match_id = '55640ec48a2aecab0e3c096c556f5435f4bb054c68930040'
    AND unix_timestamp = 33333)

然而它缺少styke：self query。

也许以下内容可能适用：

INSERT ...
ON DUPLICATE KEY UPDATE own_account = own_account;

Postgresql语法错误，其中不存在

2 个答案: