来自存储过程的php PDO结果为空

Posted 2021-05-05

这是一个例子：

SQL：

CREATE PROCEDURE my_sp(
  IN in_var VARCHAR(32)
)
BEGIN

     -- This is to avoiding the next problem:
     -- If I USE bellow: EXECUTE USING in_var NOT WORK
     -- But IF I USE: EXECUTE USING @user_invar WORKING GOOD
     SET @user_invar = in_var;

    SET @query = "SELECT * FROM my_table  WHERE my_column = ? LIMIT 1;";

    PREPARE stmt FROM @query;
    EXECUTE stmt USING @user_invar;
     SET @founded_rows = FOUND_ROWS();
    DEALLOCATE PREPARE stmt;

    IF(@founded_rows = 0)THEN
        SELECT 'ZERO_REZULTS' AS RESULTS;
    END IF;  
END;

php：

$dbh = new PDO( $connection_params );

$sql = "CALL my_sp( :in_var )";
$stmt = $dbh->prepare( $sql );
$stmt->execute( array( ':in_var' => $_POST['in_var'] ) );
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

//No errors but $rows is an empty array if @founded_rows is 0
//espected RESULTS = ZERO_REZULTS

奇怪的是，如果我从phpmyadmin接口执行程序my_sp（），那么程序就像预期的那样工作。我有：

RESULTS = ZERO_REZULTS

编辑：

除了@Bill Karwin的回答，为了按预期工作，程序必须在stmt里面有最后一个qazxsw poi：

SELECT

结束;

答案

查询需要相同数量的列的建议不是问题。存储过程生成多个不同的结果集，而不是UNION。

第一个SELECT生成零行的结果集。你仍然需要CREATE PROCEDURE my_sp( IN in_var VARCHAR(32) ) BEGIN SET @user_invar = in_var; SET @query = "SELECT * FROM my_table WHERE my_column = ? LIMIT 1;"; PREPARE stmt FROM @query; EXECUTE stmt USING @user_invar; SET @founded_rows = FOUND_ROWS(); IF(@founded_rows = 0)THEN SELECT 'ZERO_REZULTS' AS RESULTS; END IF; DEALLOCATE PREPARE stmt; 来使用这个行集，即使它是“空的”。然后你必须使用fetchAll()前进到proc返回的下一个rowset。

nextRowset()

另见：$dbh = new PDO( $connection_params ); $sql = "CALL my_sp( :in_var )"; $stmt = $dbh->prepare( $sql ); $stmt->execute( array( ':in_var' => $_POST['in_var'] ) ); do { $rowset = $stmt->fetchAll(PDO::FETCH_ASSOC); if ($rowset) { ...do something with rowset... } } while ($stmt->nextRowset());