Question

我正在扩展一些wp主题的功能，

关于预订公寓。

预订存储在名为：$ wpdb-＆gt; postmeta

的表格中

SELECT meta_value,meta_key,post_id as start_date
FROM $wpdb->postmeta 
WHERE
    meta_key = 'stay_interval' AND
    post_id IN (SELECT ID FROM $wpdb->posts WHERE
            post_type = 'tvr_booking' AND
            post_status IN ('publish', 'draft') 
    )

Wich会返回这样的东西（我只发一行）：

    array(8) {
  [0]=>
  object(stdClass)#348 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"05/16/2013";s:8:"end_date";s:10:"05/18/2013";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "4059"
    ["start_date"]=>
    string(1) "0"
  }
  [1]=>
  object(stdClass)#349 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"12/14/2012";s:8:"end_date";s:10:"12/19/2012";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "3897"
    ["start_date"]=>
    string(1) "0"
  }
  [2]=>
  object(stdClass)#350 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"12/13/2012";s:8:"end_date";s:10:"12/21/2012";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "3942"
    ["start_date"]=>
    string(1) "0"
  }
  [3]=>
  object(stdClass)#346 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"12/13/2012";s:8:"end_date";s:10:"12/19/2012";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "3943"
    ["start_date"]=>
    string(1) "0"
  }
  [4]=>
  object(stdClass)#344 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"12/21/2012";s:8:"end_date";s:10:"12/24/2012";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "3944"
    ["start_date"]=>
    string(1) "0"
  }
  [5]=>
  object(stdClass)#343 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"12/26/2012";s:8:"end_date";s:10:"12/31/2012";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "3945"
    ["start_date"]=>
    string(1) "0"
  }
  [6]=>
  object(stdClass)#292 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"12/24/2012";s:8:"end_date";s:10:"12/25/2012";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "3946"
    ["start_date"]=>
    string(1) "0"
  }
  [7]=>
  object(stdClass)#338 (4) {
    ["meta_value"]=>
    string(75) "a:2:{s:10:"start_date";s:10:"05/30/2013";s:8:"end_date";s:10:"05/31/2013";}"
    ["meta_key"]=>
    string(13) "stay_interval"
    ["post_id"]=>
    string(4) "4021"
    ["start_date"]=>
    string(1) "0"
  }
}

所以我们正在寻找meta_value的字段：

["meta_value"]=>
        string(75) "a:2:{s:10:"start_date";s:10:"05/16/2013";s:8:"end_date";s:10:"05/18/2013";}"

问题是我从未见过以这种格式存储的数据。

让我们说我想知道之间未预订的所有公寓：

两个日期：

$start_date = '05/16/2013';
$end_date = '09/16/2013';

mysql中是否有任何函数可以帮助我将日期与meta_value的字段值进行匹配？

这或多或少是我需要的：

$bookings = $wpdb->get_results( "
    SELECT ID FROM $wpdb->posts WHERE
        post_type = 'tvr_booking' AND
        post_status IN ('publish', 'draft') 
        AND ID not IN (
            SELECT post_id
            FROM $wpdb->postmeta 
            WHERE
                meta_key = 'stay_interval' AND
                somefunction(meta_value) >= '$start_date' AND
                somefunction(meta_value) <= '$end_date'
        )
" );

可以在mysql中完成吗？如果没有，我怎么能用PHP准备数据？

Answer 1

meta_value看起来像一个序列化数组。尝试unserialize

var_dump( unserialize( $row->meta_value ) );

修改

好的，所以你想找到两个日期之间的行。问题在于：我们没有MySQL可以处理的标准化数据。

这将是缓慢的（随着行数的增加而减慢），因为MySQL必须查看所有行

现在，第一步让我们尝试提取日期.. 遗憾的是，MySQL不提供任何正则表达式替换，因此我们必须使用字符串函数：

第1步：尝试提取日期

MySQL有一组有用的字符串函数，例如我们可以在这里使用的LOCATE，SUBSTRING和CHAR_LENGTH

SET @meta_value := 'a:2:{s:10:"start_date";s:10:"05/16/2013";s:8:"end_date";s:10:"05/18/2013";}'; SET @pattern := 'start_date";s:10:"'; SELECT SUBSTRING( @meta_value, LOCATE( @pattern, @meta_value ) + CHAR_LENGTH( @pattern ), 10 ) AS `start_date`; +------------+ | start_date | +------------+ | 05/16/2013 | +------------+ 1 row in set (0.00 sec) SET @pattern := 'end_date";s:10:"'; SELECT SUBSTRING( @meta_value, LOCATE( @pattern, @meta_value ) + CHAR_LENGTH( @pattern ), 10 ) AS `end_date`; +------------+ | end_date | +------------+ | 05/18/2013 | +------------+ 1 row in set (0.00 sec)

wohoo，这看起来很棒。

第2步：日期比较

现在我们要比较日期，只是尝试字符串

mysql> SELECT '05/16/2013' > CURRENT_DATE; ERROR 1267 (HY000): Illegal mix of collations (utf8_general_ci,COERCIBLE) and (latin1_swedish_ci,NUMERIC) for operation '>'
Dang，失败了 - 为什么？因为我们提取了一个字符串，MySQL比较整数，让我们做一个日期，MySQL有一个奇特的函数STR_TO_DATE

mysql> SELECT STR_TO_DATE( '05/16/2013', '%m/%d/%Y'); +----------------------------------------+ | STR_TO_DATE( '05/16/2013', '%m/%d/%Y') | +----------------------------------------+ | 2013-05-16 | +----------------------------------------+ 1 row in set (0.00 sec)

很好，还有比较？

mysql> SELECT STR_TO_DATE( '05/16/2013', '%m/%d/%Y') > CURRENT_DATE; +-------------------------------------------------------+ | STR_TO_DATE( '05/16/2013', '%m/%d/%Y') > CURRENT_DATE | +-------------------------------------------------------+ | 0 | +-------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT STR_TO_DATE( '05/16/2013', '%m/%d/%Y') < CURRENT_DATE; +-------------------------------------------------------+ | STR_TO_DATE( '05/16/2013', '%m/%d/%Y') < CURRENT_DATE | +-------------------------------------------------------+ | 1 | +-------------------------------------------------------+ 1 row in set (0.00 sec)

第3步：包含功能

完美..现在让我们将所有东西包装成两个函数

DELIMITER $$ CREATE FUNCTION `getStartDate`( metaValue TEXT ) RETURNS DATE READS SQL DATA DETERMINISTIC SQL SECURITY INVOKER BEGIN DECLARE startDate DATE; DECLARE pattern TEXT DEFAULT 'start_date";s:10:"'; SELECT STR_TO_DATE( SUBSTRING( metaValue, LOCATE( pattern, metaValue ) + CHAR_LENGTH( pattern ), 10 ), '%m/%d/%Y' ) INTO startDate; RETURN startDate; END$$ CREATE FUNCTION `getEndDate`( metaValue TEXT ) RETURNS DATE READS SQL DATA DETERMINISTIC SQL SECURITY INVOKER BEGIN DECLARE endDate DATE; DECLARE pattern TEXT DEFAULT 'end_date";s:10:"'; SELECT STR_TO_DATE( SUBSTRING( metaValue, LOCATE( pattern, metaValue ) + CHAR_LENGTH( pattern ), 10 ), '%m/%d/%Y' ) INTO endDate; RETURN endDate; END$$ DELIMITER ;

测试：

mysql> SELECT getStartDate( @meta_value ); +-----------------------------+ | getStartDate( @meta_value ) | +-----------------------------+ | 2013-05-16 | +-----------------------------+ 1 row in set (0.00 sec) mysql> SELECT getEndDate( @meta_value ); +---------------------------+ | getEndDate( @meta_value ) | +---------------------------+ | 2013-05-18 | +---------------------------+ 1 row in set (0.00 sec) mysql> SELECT getEndDate( @meta_value ) > '2013-05-12'; +------------------------------------------+ | getEndDate( @meta_value ) > '2013-05-12' | +------------------------------------------+ | 1 | +------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT getStartDate( @meta_value ) > '2013-05-12'; +--------------------------------------------+ | getStartDate( @meta_value ) > '2013-05-12' | +--------------------------------------------+ | 1 | +--------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM wpTest WHERE getStartDate( meta_value ) >= '2013-05-16' AND getEndDate( meta_value ) <= '2013-05-18'; +-----------------------------------------------------------------------------+ | meta_value | +-----------------------------------------------------------------------------+ | a:2:{s:10:"start_date";s:10:"05/16/2013";s:8:"end_date";s:10:"05/18/2013";} | +-----------------------------------------------------------------------------+ 1 row in set (0.00 sec)

像魅力一样，但是！它会变慢！

第4步：规范化数据（建议）

如果您不希望在应用程序中进行太多更改，以便将开始日期和结束日期实际存储到单独的日期字段中，则可以使用我们刚刚构建的两个函数以及一个名为triggers的酷MySQL功能来管理这些字段在后台静默，您可以将它们用于您的选择查询。

让我们先将这两个字段添加到您的表中（确保替换表名）

ALTER TABLE `wpTest` ADD `end_date` DATE NOT NULL DEFAULT '0000-00-00' AFTER `meta_value`, ADD `start_date` DATE NOT NULL DEFAULT '0000-00-00' AFTER `meta_value`;

现在我们得到了将来要用于查询的字段，让我们用它们很好的功能填充它们：

mysql> UPDATE wpTest SET start_date = getStartDate( meta_value ), end_date = getEndDate( meta_value ); Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0

现在让我们关心这些字段将来会自动维护：我们需要在INSERT和BEFORE UPDATE之前执行此操作，因此有两个触发器：

DELIMITER $$ CREATE TRIGGER `wpTest_trg_BI` BEFORE INSERT ON `wpTest` FOR EACH ROW BEGIN SET NEW.`start_date` = `getStartDate`( NEW.`meta_value` ); SET NEW.`end_date` = `getEndDate`( NEW.`meta_value` ); END$$ CREATE TRIGGER `wpTest_trg_BU` BEFORE UPDATE ON `wpTest` FOR EACH ROW BEGIN SET NEW.`start_date` = `getStartDate`( NEW.`meta_value` ); SET NEW.`end_date` = `getEndDate`( NEW.`meta_value` ); END$$ DELIMITER ;

测试触发器：

mysql> INSERT INTO wpTest (meta_value) SELECT 'a:2:{s:10:"start_date";s:10:"05/12/2013";s:8:"end_date";s:10:"05/20/2013";}'; Query OK, 1 row affected (0.00 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> INSERT INTO wpTest (meta_value) SELECT 'a:2:{s:10:"start_date";s:10:"05/10/2013";s:8:"end_date";s:10:"05/23/2013";}'; Query OK, 1 row affected (0.00 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM wpTest; +-----------------------------------------------------------------------------+------------+------------+ | meta_value | start_date | end_date | +-----------------------------------------------------------------------------+------------+------------+ | a:2:{s:10:"start_date";s:10:"05/16/2013";s:8:"end_date";s:10:"05/18/2013";} | 2013-05-16 | 2013-05-18 | | a:2:{s:10:"start_date";s:10:"05/12/2013";s:8:"end_date";s:10:"05/20/2013";} | 2013-05-12 | 2013-05-20 | | a:2:{s:10:"start_date";s:10:"05/10/2013";s:8:"end_date";s:10:"05/23/2013";} | 2013-05-10 | 2013-05-23 | +-----------------------------------------------------------------------------+------------+------------+ 3 rows in set (0.00 sec)

完美，插入有效，现在测试更新：

mysql> UPDATE wpTest SET meta_value = 'a:2:{s:10:"start_date";s:10:"05/16/2014";s:8:"end_date";s:10:"05/18/2014";}'; Query OK, 3 rows affected (0.00 sec) Rows matched: 3 Changed: 3 Warnings: 0 mysql> SELECTS * FROM wpTest; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECTS * FROM wpTest' at line 1 mysql> SELECT * FROM wpTest; +-----------------------------------------------------------------------------+------------+------------+ | meta_value | start_date | end_date | +-----------------------------------------------------------------------------+------------+------------+ | a:2:{s:10:"start_date";s:10:"05/16/2014";s:8:"end_date";s:10:"05/18/2014";} | 2014-05-16 | 2014-05-18 | | a:2:{s:10:"start_date";s:10:"05/16/2014";s:8:"end_date";s:10:"05/18/2014";} | 2014-05-16 | 2014-05-18 | | a:2:{s:10:"start_date";s:10:"05/16/2014";s:8:"end_date";s:10:"05/18/2014";} | 2014-05-16 | 2014-05-18 | +-----------------------------------------------------------------------------+------------+------------+ 3 rows in set (0.00 sec)

完美，更新也工作..现在我们不需要使用需要快速的SELECT查询中的函数：

$bookings = $wpdb->get_results( " SELECT ID FROM $wpdb->posts WHERE post_type = 'tvr_booking' AND post_status IN ('publish', 'draft') AND ID not IN ( SELECT post_id FROM $wpdb->postmeta WHERE meta_key = 'stay_interval' AND start_date >= '$start_date' AND end_date <= '$end_date' ) " );

希望这会有所帮助:)玩得开心

如何使用此数据结构匹配日期

1 个答案: