PHP调用mysqli_stmt_store_result参数为bool类型报错排查求助

1. 函数参数传递错误：mysqli_stmt_execute()的返回值是布尔类型，执行成功返回true，失败返回false，不会生成新的stmt对象。你将该函数返回的布尔值直接传入了要求参数为mysqli_stmt类型的mysqli_stmt_store_result()、mysqli_stmt_num_rows()，直接触发类型不匹配的致命错误。
2. 操作顺序错误：你在读取查询结果行数之前就提前调用mysqli_stmt_close()关闭了stmt对象，即便参数类型正确也无法正常获取行数。

修改后的可运行代码如下，核心改动是使用mysqli_prepare()返回的原始stmt对象操作结果，调整stmt关闭的顺序到读取行数之后：

// NRIC重复校验
$allaccounts = mysqli_prepare($this->conn, "SELECT 'patient' as Role, FirstName, LastName, NRIC, password FROM patients WHERE NRIC = ? 
UNION ALL 
SELECT 'doctor', FirstName, LastName, NRIC, password FROM doctor WHERE NRIC = ?  
UNION ALL 
SELECT 'nurse', FirstName, LastName, NRIC, password FROM nurse WHERE NRIC = ? 
UNION ALL 
SELECT 'admin', FirstName, LastName, NRIC, password FROM administrator WHERE NRIC = ?  
UNION ALL 
SELECT 'HospitalAdmin', FirstName, LastName, NRIC, password FROM hospitaladmin WHERE NRIC = ?  ");

mysqli_stmt_bind_param($allaccounts, "sssss", $NRIC, $NRIC, $NRIC, $NRIC, $NRIC);
mysqli_stmt_execute($allaccounts);
// 用prepare返回的stmt对象操作结果
mysqli_stmt_store_result($allaccounts);
$nricHasDuplicate = mysqli_stmt_num_rows($allaccounts) != 0;
// 读取完行数再关闭stmt
mysqli_stmt_close($allaccounts);


// 邮箱重复校验
$allaccounts_Email = mysqli_prepare($this->conn, "SELECT 'patient' as Role, FirstName, LastName, NRIC, password FROM patients WHERE Email = ? 
UNION ALL 
SELECT 'doctor', FirstName, LastName, NRIC, password FROM doctor WHERE email = ?  
UNION ALL 
SELECT 'nurse', FirstName, LastName, NRIC, password FROM nurse WHERE email = ? 
UNION ALL 
SELECT 'admin', FirstName, LastName, NRIC, password FROM administrator WHERE email = ?  
UNION ALL 
SELECT 'HospitalAdmin', FirstName, LastName, NRIC, password FROM hospitaladmin WHERE email = ?  ");

mysqli_stmt_bind_param($allaccounts_Email, "sssss", $Email, $Email, $Email, $Email, $Email);
mysqli_stmt_execute($allaccounts_Email);
// 用prepare返回的stmt对象操作结果
mysqli_stmt_store_result($allaccounts_Email);
$emailHasDuplicate = mysqli_stmt_num_rows($allaccounts_Email) != 0;
// 读取完行数再关闭stmt
mysqli_stmt_close($allaccounts_Email);


// 最终判断是否存在重复
if ($nricHasDuplicate OR $emailHasDuplicate){
    // 你原有重复时的业务逻辑
}

如果需要更高的健壮性，可以额外增加mysqli_prepare、mysqli_stmt_execute的失败判断，打印错误信息方便排查SQL语法问题。

内容的提问来源于stack exchange，提问作者yukang