MySQL插入记录，如果不存在

Question

我有以下查询

INSERT INTO `title_servicemetadatafielddefinition` (`service_id`, `field`, `behavior`, `alt_label`, `localizable`, `custom_type`, `required`, `max_length`, `help_text`) 
VALUES (319, 'custom10', 'overridable', 'Rental Period', False, 'short_text', False, NULL, '24 hour;48 hour;72 hour;1 week;30 day;3 month;6 month;1 year') 
WHERE NOT EXISTS ( SELECT * FROM `title_servicemetadatafielddefinition` WHERE `service_id` = 319 and `field` = 'custom10' ) LIMIT 1;

错误

您的SQL语法有误； 检查与您的MySQL服务器版本相对应的手册，以找到在'WHERE NOT EXISTS（SELECT * FROM title_servicemetadatafielddefinition WHERE`s'）第1行附近使用的正确语法

并且在尝试执行时失败，无法找出错误的语法

Answer 1

如果行不存在，将在下面的查询中插入，如果行已存在，则将其忽略，但请确保此处的service_id应该是主键或唯一键。

INSERT IGNORE INTO `title_servicemetadatafielddefinition` (`service_id`, `field`, `behavior`, `alt_label`, `localizable`, `custom_type`, `required`, `max_length`, `help_text`) 
VALUES (319, 'custom10', 'overridable', 'Rental Period', False, 'short_text', False, NULL, '24 hour;48 hour;72 hour;1 week;30 day;3 month;6 month;1 year') 

Answer 2

尝试这个：

INSERT INTO `title_servicemetadatafielddefinition` (`service_id`, `field`, `behavior`, `alt_label`, `localizable`, `custom_type`, `required`, `max_length`, `help_text`) 
SELECT 319, 'custom10', 'overridable', 'Rental Period', False, 'short_text', False, NULL, '24 hour;48 hour;72 hour;1 week;30 day;3 month;6 month;1 year'
FROM (SELECT 1) x
LEFT JOIN `title_servicemetadatafielddefinition` t
  ON t.`service_id` = 319 and t.`field` = 'custom10'
WHERE t.service_id IS NULL

Answer 3

您在INSERT STATEMENT中写了'Limit'。 我认为，限制应该出现在SELECT语句中。

INSERT INTO `title_servicemetadatafielddefinition` (`service_id`, `field`, `behavior`, `alt_label`, `localizable`, `custom_type`, `required`, `max_length`, `help_text`) 
VALUES (319, 'custom10', 'overridable', 'Rental Period', False, 'short_text', False, NULL, '24 hour;48 hour;72 hour;1 week;30 day;3 month;6 month;1 year') 
WHERE NOT EXISTS ( SELECT * FROM `title_servicemetadatafielddefinition` WHERE `service_id` = 319 and `field` = 'custom10' LIMIT 1); 

在MySQL的“ INSERT”中使用“ LIMIT”？