MySQL 存储过程返回 0 行

Question

当我在 phpMyAdmin（SQL 选项卡）中像这样调用过程时，它可以工作：

CALL `test_discount`('022979', 1101, 1, 'W', 100, @p5); SELECT @p5 AS `discount`;

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但是，当我像这样在PHP 中调用它时：

$res = $conn->query("CALL `test_discount`('022979', 1101, 1, 'W', 100, @p5); SELECT @p5 AS `discount`;");

我收到语法错误：You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'SELECT @p5 AS discount' at line 1

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如何让它在 PHP 中工作？

Answer 1

问题是 mySQL 不支持单个 query 调用中的多个语句：http://php.net/manual/en/mysqli.quickstart.multiple-statement.php

例如给定以下代码（来自上面的链接）：

<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
$res    = $mysqli->query("SELECT 1; DROP TABLE mysql.user");
if (!$res) {
    echo "Error executing query: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>

您将收到以下输出：

Error executing query: (1064) You have an error in your SQL syntax;
check the manual that corresponds to your MySQL server version for the right syntax 
to use near 'DROP TABLE mysql.user' at line 1

解决方案：使用多查询：

$mysqli->multi_query( "CALL `test_discount`('022979', 1101, 1, 'W', 100, @p5); SELECT @p5 AS `discount`;" );

编辑：另见：

• PHP + MySql + Stored Procedures, how do I get access an "out" value?
• http://www.joeyrivera.com/2009/using-mysql-stored-procedures-with-php-mysqlmysqlipdo/

使用multi_query调用过程的例子：

$mysqli = new mysqli(  "HOST", "USR", "PWD", "DBNAME" );
$ivalue=1;
$res = $mysqli->multi_query( "CALL myproc($ivalue,@x);SELECT @x" );
if( $res ) {
  $results = 0;
  do {
    if ($result = $mysqli->store_result()) {
      printf( "<b>Result #%u</b>:<br/>", ++$results );
      while( $row = $result->fetch_row() ) {
        foreach( $row as $cell ) echo $cell, "&nbsp;";
      }
      $result->close();
      if( $mysqli->more_results() ) echo "<br/>";
    }
  } while( $mysqli->next_result() );
}
$mysqli->close();