pg_field_table

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

pg_field_table — Returns the name or oid of the tables field

说明

pg_field_table(PgSql\Result $result, int $field, bool $oid_only = false): string|int|false

pg_field_table() returns the name of the table that field belongs to, or the table's oid if oid_only is true.

参数

result: PgSql\Result 实例，由 pg_query()、pg_query_params() 或者 pg_execute()（等）返回。
field: Field number, starting from 0.
oid_only: By default the tables name that field belongs to is returned but if oid_only is set to true, then the oid will instead be returned.

返回值

On success either the fields table name or oid, 或者在失败时返回 false.

更新日志

版本	说明
8.1.0	现在 `result` 参数接受 PgSql\Result 实例，之前接受 resource。

示例

示例 #1 Getting table information about a field

<?php
$dbconn = pg_connect("dbname=publisher") or die("Could not connect");

$res = pg_query($dbconn, "SELECT bar FROM foo");

echo pg_field_table($res, 0);
echo pg_field_table($res, 0, true);

$res = pg_query($dbconn, "SELECT version()");
var_dump(pg_field_table($res, 0));
?>

以上示例的输出类似于：

foo
14379580

bool(false)

注释

注意:
Returning the oid is much faster than returning the table name because fetching the table name requires a query to the database system table.

参见

pg_field_name() - 返回字段名
pg_field_type() - 返回相应字段编号的类型名称

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用户贡献的备注 2 notes

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strata_ranger at hotmail dot com ¶

15 years ago

pg_field_table is primarily useful for queries that involve joins between multiple tables, e.g:

<?php
$res = pg_query("SELECT table1.foo, table2.bar FROM table1 JOIN table2");
echo pg_field_table($res, 0); // Outputs 'table1'
echo pg_field_table($res, 1); // Outputs 'table2'
?>

However, be aware of a few easy 'gotchas':

1- If your query contains static values in its select-list, pg_field_table() will yield FALSE for those fields (because it was a static value, not one fetched from a table):

<?php
$res = pg_query("SELECT 'foo', bar FROM table");
echo pg_field_table($res, 0); // FALSE
echo pg_field_table($res, 1); // Outputs 'table'
?>

2- If you UNION two queries together from different tables, pg_field_table() will return FALSE for all fields:

<?php
$res = pg_query("(Select foo, bar from table1) UNION (Select foo, bar from table2)");
echo pg_field_table($res, 0); // FALSE
echo pg_field_table($res, 1); // FALSE
?>

down

giultar at gmail dot com ¶

4 years ago

this function return an OID even if your field comes from a view or a select but return FALSE if your field comes from an UNION select