Mysql SQL元相关查询

您好，我在mysql中有两个表，分别是table post和table post\u meta 我想根据post_元键/值数据查询post表。 示例中的第一个查询with=statment正在工作，第二个查询with！=状态不工作。有什么帮助吗

如何排除带有postETA键[hide]=value['1']的帖子？

这里是预期的结果

范例

//显示post，其中POSTETA键[hide]=value

2行
1测试后1 3 1隐藏1

3测试后3 4 3隐藏1

//显示Posteta键所在的位置[隐藏]！=值

0行

//为什么?？此查询必须返回post 2

数据库模式

----table post

CREATE TABLE `post` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;


INSERT INTO `post` VALUES ('1', 'Post test 1');
INSERT INTO `post` VALUES ('2', 'Post test 2');
INSERT INTO `post` VALUES ('3', 'Post test 3');


----table post_meta

CREATE TABLE `post_meta` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `postid` int(11) DEFAULT NULL,
  `key` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  `value` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

INSERT INTO `post_meta` VALUES ('1', '1', 'name', 'leone');
INSERT INTO `post_meta` VALUES ('2', '2', 'name', 'mario');
INSERT INTO `post_meta` VALUES ('3', '1', 'hide', '1');
INSERT INTO `post_meta` VALUES ('4', '3', 'hide', '1');

---

由于该条件，第二个查询不起作用

mt1.`key` = 'hide'

仔细查看查询

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

你有一个条件

mt1.`key` = 'hide'

那么你正在使用

AND CAST(mt1.`value` AS CHAR) != 1

现在，在

post_meta

表检查中，没有包含

key = hide and value != '1'

因此，条件失败，结果为0

这是你提供的

INSERT INTO `post_meta` VALUES ('1', '1', 'name', 'leone');
INSERT INTO `post_meta` VALUES ('2', '2', 'name', 'mario');
INSERT INTO `post_meta` VALUES ('3', '1', 'hide', '1');
INSERT INTO `post_meta` VALUES ('4', '3', 'hide', '1');

根据问题中提供的更新，您可以获得以下结果：

SELECT *
FROM
post AS mt0
INNER JOIN post_meta mt1
ON mt0.id = mt1.postid
AND mt0.id NOT IN (
  select postid from post_meta where `key` = 'hide' AND CAST(`value` AS CHAR) = 1
);

---

由于该条件，第二个查询不起作用

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) = 1
    )

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

mt1.`key` = 'hide'

仔细查看查询

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

你有一个条件

mt1.`key` = 'hide'

那么你正在使用

AND CAST(mt1.`value` AS CHAR) != 1

现在，在

post_meta

表检查中，没有包含

key = hide and value != '1'

因此，条件失败，结果为0

这是你提供的

INSERT INTO `post_meta` VALUES ('1', '1', 'name', 'leone');
INSERT INTO `post_meta` VALUES ('2', '2', 'name', 'mario');
INSERT INTO `post_meta` VALUES ('3', '1', 'hide', '1');
INSERT INTO `post_meta` VALUES ('4', '3', 'hide', '1');

根据问题中提供的更新，您可以获得以下结果：

SELECT *
FROM
post AS mt0
INNER JOIN post_meta mt1
ON mt0.id = mt1.postid
AND mt0.id NOT IN (
  select postid from post_meta where `key` = 'hide' AND CAST(`value` AS CHAR) = 1
);

---

由于该条件，第二个查询不起作用

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) = 1
    )

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

mt1.`key` = 'hide'

仔细查看查询

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

你有一个条件

mt1.`key` = 'hide'

那么你正在使用

AND CAST(mt1.`value` AS CHAR) != 1

现在，在

post_meta

表检查中，没有包含

key = hide and value != '1'

因此，条件失败，结果为0

这是你提供的

INSERT INTO `post_meta` VALUES ('1', '1', 'name', 'leone');
INSERT INTO `post_meta` VALUES ('2', '2', 'name', 'mario');
INSERT INTO `post_meta` VALUES ('3', '1', 'hide', '1');
INSERT INTO `post_meta` VALUES ('4', '3', 'hide', '1');

根据问题中提供的更新，您可以获得以下结果：

SELECT *
FROM
post AS mt0
INNER JOIN post_meta mt1
ON mt0.id = mt1.postid
AND mt0.id NOT IN (
  select postid from post_meta where `key` = 'hide' AND CAST(`value` AS CHAR) = 1
);

---

由于该条件，第二个查询不起作用

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) = 1
    )

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

mt1.`key` = 'hide'

仔细查看查询

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )

你有一个条件

mt1.`key` = 'hide'

那么你正在使用

AND CAST(mt1.`value` AS CHAR) != 1

现在，在

post_meta

表检查中，没有包含

key = hide and value != '1'

因此，条件失败，结果为0

这是你提供的

INSERT INTO `post_meta` VALUES ('1', '1', 'name', 'leone');
INSERT INTO `post_meta` VALUES ('2', '2', 'name', 'mario');
INSERT INTO `post_meta` VALUES ('3', '1', 'hide', '1');
INSERT INTO `post_meta` VALUES ('4', '3', 'hide', '1');

根据问题中提供的更新，您可以获得以下结果：

SELECT *
FROM
post AS mt0
INNER JOIN post_meta mt1
ON mt0.id = mt1.postid
AND mt0.id NOT IN (
  select postid from post_meta where `key` = 'hide' AND CAST(`value` AS CHAR) = 1
);

---

谢谢阿比克的回答。如何排除Posteta hide=1的帖子？欢迎！我没有得到你能在问题中添加你期望的结果吗。这将使我更容易将其可视化。不，我还想排除并用id 1发布此帖子的原因。key[hide]=1谢谢您的回答。如何排除Posteta hide=1的帖子？欢迎！我没有得到你能在问题中添加你期望的结果吗。这将使我更容易将其可视化。不，我还想排除并用id 1发布此帖子的原因。key[hide]=1谢谢您的回答。如何排除Posteta hide=1的帖子？欢迎！我没有得到你能在问题中添加你期望的结果吗。这将使我更容易将其可视化。不，我还想排除并用id 1发布此帖子的原因。key[hide]=1谢谢您的回答。如何排除Posteta hide=1的帖子？欢迎！我没有得到你能在问题中添加你期望的结果吗。这将使我更容易将其可视化。不，我还想排除并用id 1发布此帖子的原因。key[hide]=1

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) = 1
    )

SELECT
    *
FROM
    post AS mt0
INNER JOIN post_meta AS mt1 ON mt0.id = mt1.postid
WHERE
    (
        mt1.`key` = 'hide'
        AND CAST(mt1.`value` AS CHAR) != 1
    )