PHP 手册
后退 |  | 前进

# PDO::exec

(no version information, might be only in CVS)

PDO::exec -- Execute an SQL statement and return the number of affected rows

## 说明

int PDO::exec ( string statement )

PDO::exec() executes an SQL statement in a single function call, returning the number of rows affected by the statement.

PDO::exec() does not return results from a SELECT statement. For a SELECT statement that you only need to issue once during your program, consider issuing PDO::query(). For a statement that you need to issue multiple times, prepare a PDOStatement object with PDO::prepare() and issue the statement with PDOStatement::execute().

## 参数

statement

  The SQL statement to prepare and execute.

## 返回值

PDO::exec() returns the number of rows that were modified or deleted by the SQL statement you issued. If no rows were affected, PDO::exec() returns 0.

警告
本函数可能返回布尔值 `FALSE`，但也可能返回一个与 `FALSE` 等值的非布尔值，例如 0 或者 ""。请参阅布尔类型章节以获取更多信息。应使用 === 运算符来测试本函数的返回值。

The following example incorrectly relies on the return value of PDO::exec(), wherein a statement that affected 0 rows results in a call to die():

`<?php $db->exec() or die($db->errorInfo()); ?>`

## 范例

例子 1. Issuing a DELETE statement

Count the number of rows deleted by a DELETE statement with no WHERE clause.

`<?php $dbh = new PDO('odbc:sample', 'db2inst1', 'ibmdb2'); /* Delete all rows from the FRUIT table */ $count = $dbh->exec("DELETE FROM fruit WHERE colour = 'red'"); /* Return number of rows that were deleted */ print("Deleted $count rows.\n"); ?>`

上例将输出：

    Deleted 1 rows.

## 参见

PDO::prepare()
PDO::query()
PDOStatement::execute()

后退 | 起点 | 前进
PDO::errorInfo | 上一级 | PDO::getAttribute