# pg_query_params

(PHP 5 >= 5.1.0, PHP 7)

pg_query_params — Submits a command to the server and waits for the result, with the ability to pass parameters separately from the SQL command text

### 说明

pg_query_params ([ resource `$connection` ], string `$query` , array `$params` ) : resource

Submits a command to the server and waits for the result, with the ability to pass parameters separately from the SQL command text.

pg_query_params() is like pg_query(), but offers additional functionality: parameter values can be specified separately from the command string proper. pg_query_params() is supported only against PostgreSQL 7.4 or higher connections; it will fail when using earlier versions.

If parameters are used, they are referred to in the `query` string as $1, $2, etc. The same parameter may appear more than once in the `query`; the same value will be used in that case. `params` specifies the actual values of the parameters. A `NULL` value in this array means the corresponding parameter is SQL NULL.

The primary advantage of pg_query_params() over pg_query() is that parameter values may be separated from the `query` string, thus avoiding the need for tedious and error-prone quoting and escaping. Unlike pg_query(), pg_query_params() allows at most one SQL command in the given string. (There can be semicolons in it, but not more than one nonempty command.)

### 参数

`connection`

  PostgreSQL database connection resource. When `connection` is not present, the default connection is used. The default connection is the last connection made by pg_connect() or pg_pconnect().

`query`

  The parameterized SQL statement. Must contain only a single statement. (multiple statements separated by semi-colons are not allowed.) If any parameters are used, they are referred to as $1, $2, etc.

  User-supplied values should always be passed as parameters, not interpolated into the query string, where they form possible SQL injection attack vectors and introduce bugs when handling data containing quotes. If for some reason you cannot use a parameter, ensure that interpolated values are properly escaped.

`params`

  An array of parameter values to substitute for the $1, $2, etc. placeholders in the original prepared query string. The number of elements in the array must match the number of placeholders.

  Values intended for bytea fields are not supported as parameters. Use pg_escape_bytea() instead, or use the large object functions.

### 返回值

A query result resource on success 或者在失败时返回 `FALSE`.

### 范例

Example #1 Using pg_query_params()

    <?php
    // Connect to a database named "mary"
    $dbconn = pg_connect("dbname=mary");

    // Find all shops named Joe's Widgets.  Note that it is not necessary to
    // escape "Joe's Widgets"
    $result = pg_query_params($dbconn, 'SELECT * FROM shops WHERE name = $1', array("Joe's Widgets"));

    // Compare against just using pg_query
    $str = pg_escape_string("Joe's Widgets");
    $result = pg_query($dbconn, "SELECT * FROM shops WHERE name = '{$str}'");

    ?>

### 参见

- pg_query() - 执行查询