ORDER BY date 并包括没有日期的记录？ [复制]答案

【问题标题】：ORDER BY date and include records that don't have date? [duplicate]ORDER BY date 并包括没有日期的记录？ [复制]
【发布时间】：2013-04-21 06:46:30
【问题描述】：

是否可以按 DATE 对记录进行排序，但仍包括没有日期值的记录？后者将被放置在列表的末尾。

这是一个 wordpress 查询，但我认为我的问题在这里更合适：

$sql = "SELECT * FROM $wpdb->postmeta";
$sql .= " INNER JOIN $wpdb->posts ON $wpdb->postmeta.post_id = $wpdb->posts.ID";
$sql .= " WHERE $wpdb->posts.post_type = 'task'";
$sql .= " AND $wpdb->posts.post_parent IN ( SELECT `ID` FROM $wpdb->posts WHERE `post_type` = 'task_list' AND `post_parent` IN ( SELECT `ID` FROM $wpdb->posts WHERE `post_status` = 'publish' AND `post_type` = 'project' ) )";
$sql .= " AND $wpdb->postmeta.post_id IN ( SELECT `post_id` FROM $wpdb->postmeta WHERE $wpdb->postmeta.meta_key = '_completed' AND $wpdb->postmeta.meta_value = '0' )";
$sql .= " AND $wpdb->postmeta.post_id IN ( SELECT `post_id` FROM $wpdb->postmeta WHERE $wpdb->postmeta.meta_key = '_assigned' AND $wpdb->postmeta.meta_value = '%s' )";
$sql .= " AND $wpdb->postmeta.meta_key = '_due'";
$sql .= " AND CAST( $wpdb->postmeta.meta_value AS DATE )";
$sql .= " GROUP BY $wpdb->posts.ID";
$sql .= " ORDER BY $wpdb->postmeta.meta_value ASC";

如何修改？

【问题讨论】：

是的，有可能。你试过了吗？
AND CAST( $wpdb->postmeta.meta_value AS DATE ) 应该达到什么目的？

标签： php mysql datetime

【解决方案1】：

只需删除条件 WHERE … CAST( $wpdb->postmeta.meta_value AS DATE )，因为这会从结果中删除 NULL 日期。没有它，行将被包括在内，并且排序不会改变这一点。然后，您可以在 ORDER BY 部分中重新插入该表达式以按日期排序。 NULL 值将被排序到开头，即你的比较小于非NULL 值。

【讨论】：

【解决方案2】：

这个成功了：

$sql = "SELECT * FROM $wpdb->postmeta";
$sql .= " INNER JOIN $wpdb->posts ON $wpdb->postmeta.post_id = $wpdb->posts.ID";
$sql .= " WHERE $wpdb->posts.post_type = 'task'";
$sql .= " AND $wpdb->posts.post_parent IN ( SELECT `ID` FROM $wpdb->posts WHERE `post_type` = 'task_list' AND `post_parent` IN ( SELECT `ID` FROM $wpdb->posts WHERE `post_status` = 'publish' AND `post_type` = 'project' ) )";
$sql .= " AND $wpdb->postmeta.post_id IN ( SELECT `post_id` FROM $wpdb->postmeta WHERE $wpdb->postmeta.meta_key = '_completed' AND $wpdb->postmeta.meta_value = '0' )";
$sql .= " AND $wpdb->postmeta.post_id IN ( SELECT `post_id` FROM $wpdb->postmeta WHERE $wpdb->postmeta.meta_key = '_assigned' AND $wpdb->postmeta.meta_value = '%s' )";
$sql .= " AND $wpdb->postmeta.meta_key = '_due'";
$sql .= " GROUP BY $wpdb->posts.ID";
$sql .= " ORDER BY $wpdb->posts.ID ASC, CAST( $wpdb->postmeta.meta_value AS DATE ) ASC";

感谢您的帮助！

【讨论】：

【解决方案3】：

尝试 SELECT * FROM TABLE ORDER BY date

【讨论】：