$filter['field'] = ['neq','not null']; //不为空
$filter['field'] = null; //null
或者
$filter[''] = [Db::raw('field IS NULL')]
$filter[''] = [Db::raw('field IS NOT NULL')]
本文深入探讨了数据库查询中关于字段是否为空的判断方法,通过使用不同的SQL语句,如'notnull', 'ISNULL', 'ISNOTNULL',来实现对数据库字段的有效筛选。这不仅适用于初学者,也对有一定经验的开发者提供了新的视角。
$filter['field'] = ['neq','not null']; //不为空
$filter['field'] = null; //null
或者
$filter[''] = [Db::raw('field IS NULL')]
$filter[''] = [Db::raw('field IS NOT NULL')]
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