这是我的(PostgreSQL)表--test=>createtablepeople(namevarcharprimarykey,marriage_statusvarchar);test=>insertintopeoplevalues('Ken','married');test=>insertintopeoplevalues('May','single');test=>insertintopeoplevalues('Joe',NULL);我想选择所有未已知已婚的人，即包括婚姻状态为NULL的人。这不工作--test=>select*frompeoplewheremarriage_sta

这是我的(PostgreSQL)表--test=>createtablepeople(namevarcharprimarykey,marriage_statusvarchar);test=>insertintopeoplevalues('Ken','married');test=>insertintopeoplevalues('May','single');test=>insertintopeoplevalues('Joe',NULL);我想选择所有未已知已婚的人，即包括婚姻状态为NULL的人。这不工作--test=>select*frompeoplewheremarriage_sta