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pg_query

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_query执行查询

说明

pg_query(PgSql\Connection $connection = ?, string $query): PgSql\Result|false

pg_query() 在特定数据库 connection 上执行 querypg_query_params() 在大多数情况下应该是首选。

如果发生错误并返回 false,那么在连接有效时可以使用 pg_last_error() 函数检索错误的详细信息。

注意: 尽管可以省略 connection,但不建议这样做,因为可能会导致脚本中的错误难以发现。

注意:

本函数以前的名字为 pg_exec()pg_exec() 因为兼容性原因仍可使用,但鼓励用户使用新名称。

参数

connection

An PgSql\Connection instance. When connection is unspecified, the default connection is used. The default connection is the last connection made by pg_connect() or pg_pconnect().

警告

As of PHP 8.1.0, using the default connection is deprecated.

query

要执行的 SQL 语句。当多个语句传递给函数时,将作为一个事务自动执行,除非查询字符串中包含明确的 BEGIN/COMMIT 命令。但是,不建议在一个函数调用中使用多个事务。

警告

用户提供的数据作为字符串插入值非常危险,很可能导致 SQL 注入漏洞。在大多数情况下,应该首选 pg_query_params(),将用户提供的值作为参数传递,而不是将它们替换为查询字符串。

任何用户提供的数据,都应该正确转义,然后直接替换为查询字符串。

返回值

成功时为 PgSql\Result 实例, 或者在失败时返回 false

更新日志

版本 说明
8.1.0 现在返回 PgSql\Result 实例,之前返回 resource
8.1.0 现在 connection 参数接受 PgSql\Connection 实例,之前接受 resource

示例

示例 #1 pg_query() 示例

<?php

$conn
= pg_pconnect("dbname=publisher");
if (!
$conn) {
echo
"An error occurred.\n";
exit;
}

$result = pg_query($conn, "SELECT author, email FROM authors");
if (!
$result) {
echo
"An error occurred.\n";
exit;
}

while (
$row = pg_fetch_row($result)) {
echo
"Author: $row[0] E-mail: $row[1]";
echo
"<br />\n";
}

?>

示例 #2 使用多条语句的 pg_query()

<?php

$conn
= pg_pconnect("dbname=publisher");

// 这些语句将作为一个事务执行

$query = "UPDATE authors SET author=UPPER(author) WHERE id=1;";
$query .= "UPDATE authors SET author=LOWER(author) WHERE id=2;";
$query .= "UPDATE authors SET author=NULL WHERE id=3;";

pg_query($conn, $query);

?>

参见

添加备注

用户贡献的备注 9 notes

up
5
a dot mcruer at live dot com
11 years ago
A quick note for novice users: when gathering input from fields on a web form that maintains a database connection, *never* use pg_query to do queries from the field. Always sanitize input using pg_prepare and pg_execute.
up
4
zoli at makettinfo.hu
18 years ago
It would be better this way:

<?php
$result
=pg_query($conn, "SELECT COUNT(*) AS rows FROM x WHERE a=b;");
if (!
$result) {
echo
"query did not execute";
}
if (
$line = pg_fetch_assoc($result)) {
if (
$line['rows'] == 0) {
echo
"0 records"
}
}
else {
while (
$row = pg_fetch_array($result)) {
//do stuff with $row
}
}
?>

This solution doesn't raise the load of the system with the move of matching rows (perhaps 0,1, perhaps 100, 1000, ... rows)
up
4
jsuzuki at spamcop dot net
19 years ago
expanding on the note left by "cmoore" -

To check to see if the recordset returned no records,

<?php
$result
=pg_query($conn, "SELECT * FROM x WHERE a=b;");
if (!
$result) {
echo
"query did not execute";
}
$rs = pg_fetch_assoc($result);
if (!
$rs) {
echo
"0 records"
}
?>

-jack
up
2
mentat at azsoft dot pl
22 years ago
$GLOBALS["PG_CONNECT"]=pg_connect(...);
....

function query ($sqlQuery,$var=0) {
if (!$GLOBALS["PG_CONNECT"]) return 0;
$lev=error_reporting (8); //NO WARRING!!
$result=pg_query ($sqlQuery);
error_reporting ($lev); //DEFAULT!!
if (strlen ($r=pg_last_error ($GLOBALS["PG_CONNECT"]))) {
if ($var) {
echo "<p color=\"red\">ERROR:<pre>";
echo $sqlQuery;
echo "</pre>";
echo $r;
echo "&lt/p>";
}
close_db ();
return 0;
}
return $result;
}
up
1
cmoore
19 years ago
One thing to note that wasn't obvious to me at first. If your query returns zero rows, that is not a "failed" query. So the following is wrong:
$result=pg_query($conn, "SELECT * FROM x WHERE a=b;");
if (!$result) {
echo "No a=b in x\n";
}

pg_query returns FALSE if the query can not be executed for some reason. If the query is executed but returns zero rows then you get back a resul with no rows.
up
0
mankyd
18 years ago
There was a typo in the code that I posted:

<?php
$result
=pg_query($conn, "SELECT * FROM x WHERE a=b;");
if (!
$result) {
echo
"query did not execute";
}
if (
pg_num_rows($result) == 0) {
echo
"0 records"
}
else {
while (
$row = pg_fetch_array($result)) {
//do stuff with $row
}
}
?>
up
-1
Akbar
20 years ago
Use pg_query to call your stored procedures, and use pg_fetch_result when getting a value (like a smallint as in this example) returned by your stored procedure.

<?php
$pgConnection
= pg_connect("dbname=users user=me");

$userNameToCheckFor = "metal";

$result = pg_query($pgConnection, "SELECT howManyUsersHaveThisName('$userNameToCheckFor')");

$count = pg_fetch_result($result, 0, 'howManyUsersHaveThisName');
?>
up
-2
mankyd
18 years ago
Improving upon what jsuzuki said:

It's probably better to use pg_num_rows() to see if no rows were returned, as that leaves the resultset cursor pointed to the first row so you can use it in a loop.

Example:

<?php
$result
=pg_query($conn, "SELECT * FROM x WHERE a=b;");
if (!
$result) {
echo
"query did not execute";
}
if (
pg_num_rows($result) == 0) {
echo
"0 records"
}
else {
while (
$row = pg_fetch_array($result) {
//do stuff with $row
}
}
?>

I, personally, also find it more readable.
up
-2
Anonymous
10 years ago
Here is my small function to make it easier for me to use data from select queries (attention, it is sensitive to sql injection)
<?php
function requestToDB($connection,$request){
if(!
$result=pg_query($connection,$request)){
return
False;
}
$combined=array();
while (
$row = pg_fetch_assoc($result)) {
$combined[]=$row;
}
return
$combined;
}
?>

Example:
<?php
$conn
= pg_pconnect("dbname=mydatabase");

$results=requestToDB($connect,"select * from mytable");

//You can now access a "cell" of your table like this:
$rownumber=0;
$columname="mycolumn";

$mycell=$results[$rownumber][$columname];
var_dump($mycell);
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