PDO::query()

(PHP 5 >= 5.1.0, PHP 7, PECL pdo >= 0.2.0)

执行 SQL 语句，以 PDOStatement 对象形式返回结果集

说明

publicPDO::query(string $statement): PDOStatementpublicPDO::query(string $statement,int$PDO::FETCH_COLUMN,int $colno): PDOStatementpublicPDO::query(string $statement,int$PDO::FETCH_CLASS,string $classname,array $ctorargs): PDOStatementpublicPDO::query(string $statement,int$PDO::FETCH_INTO,object $object): PDOStatement

PDO::query()在单次函数调用内执行 SQL 语句，以 PDOStatement 对象形式返回结果集（如果有数据的话）。

如果反复调用同一个查询，用PDO::prepare()准备 PDOStatement 对象，并用PDOStatement::execute()执行语句，将具有更好的性能。

如果没有完整获取结果集内的数据，就调用下一个PDO::query()，将可能调用失败。应当在执行下一个PDO::query()前，先用PDOStatement::closeCursor()释放数据库PDOStatement 关联的资源。

Note:

如果传入函数的参数数量超过一个，多余的参数将相当于调用结果对象PDOStatement::setFetchMode()方法。

参数

$statement

需要准备、执行的 SQL 语句。

查询里的数据应该用恰当的形式转义。

返回值

PDO::query()返回 PDOStatement 对象，或在失败时返回FALSE。

范例

展示 PDO::query 的使用

PDO::query()一个不错的功能是：执行 SELECT 语句，并能够循环遍历结果集。

以上例程会输出：

apple   red     150
banana  yellow  250
kiwi    brown   75
lemon   yellow  25
orange  orange  300
pear    green   150
watermelon      pink    90

参见

• PDO::exec() 执行一条 SQL 语句，并返回受影响的行数
• PDO::prepare() 准备要执行的语句，并返回语句对象
• PDOStatement::execute() 执行一条预处理语句

The handling of errors by this function is controlled by the attribute PDO::ATTR_ERRMODE.
Use the following to make it throw an exception: 

> When query() fails, the boolean false is returned. 
I think that is "Silent Mode".
If that set attribute ErrorMode "Exception Mode"
then that throw PDOException.
 $pdoObj = new PDO( $dsn, $user, $pass );
 $pdoObj->setAttribute("PDO::ATTR_ERRMODE", PDO::ERRMODE_EXCEPTION);

After a lot of hours working with DataLink on Oracle->MySQL and PDO we (me and Adriano Rodrigues, that solve it) discover that PDO (and oci too) need the attribute AUTOCOMMIT set to FALSE to work correctly with.
There's 3 ways to set autocommit to false: On constructor, setting the atribute after construct and before query data or initiating a Transaction (that turns off autocommit mode)
The examples:


To use DataLinks on oci just use OCI_DEFAULT on oci_execute() function;

Trying to pass like second argument PDO::FETCH_ASSOC it still work.
So passing FETCH TYPE like argument seems work.
This save you from something like:

Example: 

If someone is suffering of the "MySQL server has gone away" problem after executing multiple queries, this is a solution that solved it for me. It's similar to the one needed for the exact same problem in mysqli.

I found this only works using prepare and execute this way, not if you 
directly execute the query with query().

The Documentation doesn’t mention this, but you can use a fetch style as a second parameter. For example: 

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