Question

SELECT t1.case_num AS casenum, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
     NULL, NULL
FROM luponcase_tbl t1
WHERE t1.case_num = :id AND t1.status = :active
UNION
SELECT mhearing_number, mhearing_status, mhearing_number, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL
FROM luponcase_mediation_tbl t4
WHERE t4.case_num = :id AND t4.status = :active
UNION
SELECT mfileblob, mfile_type, mfilesize, mhearing_number, mnameoffile, NULL, NULL, NULL,
    NULL, NULL
FROM luponcase_mediation_reference_tbl t5
WHERE t5.case_num = :id AND t5.status = :active

这是我的联盟的sql，我没有得到结果所以我试图回应结果

while ($selected_row = $stmt->fetch(PDO::FETCH_ASSOC)) {
                        print_r($selected_row);
}

令我惊讶的是结果是

Array ( [casenum] => 14 [NULL] => )

我假设第一个值是正确的，那么NULL列不是。如何使我只获得除NULL之外的列。

Answer 1

当您连接到数据库时，您可以设置一些属性来控制PDO在数据库查询返回时处理Null和空字符串的方式

UNION SELECT mysql php pdo没有值返回

1 个答案: