mysql_field_seek
The function below takes a function and returns the col->table mapping as an array.
For example:
$query = “SELECT a.id AS a_id, b.id b_id FROM atable AS a, btable b”
$cols = queryAlias($query);
print_r($cols);
Returns:
Array
(
[a] => atable
[b] => btable
)
I can't promise it's perfect, but this function never hit production cause I ended up using mysqli methods instead.
Enjoy
-Jorge
/**
* Takes in a query and returns the alias->table mapping.
*
* @param string $query
* @return array of alias mapping
*/
function queryAlias ( $query ) {
//Make it all lower, we ignore case
$substr = strtolower($query);
//Remove any subselects
$substr = preg_replace ( ‘/\(.*\)/’, ”, $substr);
//Remove any special charactors
$substr = preg_replace ( ‘/[^a-zA-Z0-9_,]/’, ‘ ‘, $substr);
//Remove any white space
$substr = preg_replace(‘/\s\s+/’, ‘ ‘, $substr);
//Get everything after FROM
$substr = strtolower(substr($substr, strpos(strtolower($substr),‘ from ‘) + 6));
//Rid of any extra commands
$substr = preg_replace(
Array(
‘/ where .*+$/’,
‘/ group by .*+$/’,
‘/ limit .*+$/’ ,
‘/ having .*+$/’ ,
‘/ order by .*+$/’,
‘/ into .*+$/’
), ”, $substr);
//Remove any JOIN modifiers
$substr = preg_replace(
Array(
‘/ left /’,
‘/ right /’,
‘/ inner /’,
‘/ cross /’,
‘/ outer /’,
‘/ natural /’,
‘/ as /’
), ‘ ‘, $substr);
//Replace JOIN statements with commas
$substr = preg_replace(Array(‘/ join /’, ‘/ straight_join /’), ‘,’, $substr);
$out_array = Array();
//Split by FROM statements
$st_array = split (‘,’, $substr);
foreach ($st_array as $col) {
$col = preg_replace(Array(‘/ on .*+/’), ”, $col);
$tmp_array = split(‘ ‘, trim($col));
//Oh no, something is wrong, let’s just continue
if (!isset($tmp_array[0]))
continue;
$first = $tmp_array[0];
//If the “AS” is set, lets include that, if not, well, guess this table isn’t aliased.
if (isset($tmp_array[1]))
$second = $tmp_array[1];
else
$second = $first;
if (strlen($first))
$out_array[$second] = $first;
}
return $out_array;
}
mysql_field_table
(PHP 4, PHP 5, PECL mysql:1.0)
mysql_field_table — Get name of the table the specified field is in
說明
string mysql_field_table
( resource $result
, int $field_offset
)
Returns the name of the table that the specified field is in.
參數
- result
-
回傳類型為 resource 的結果集。該結果集從 mysql_query() 的呼叫中得到。
- field_offset
-
數字形式的欄位偏移量。field_offset 開始於 0。如果 field_offset 不存在，系統會發出 E_WARNING 級別的警告信息。
Return值
The name of the table on success.
範例
Example#1 A mysql_field_table() example
<?php
$query = "SELECT account.*, country.* FROM account, country WHERE country.name = 'Portugal' AND account.country_id = country.id";
// get the result from the DB
$result = mysql_query($query);
// Lists the table name and then the field name
for ($i = 0; $i < mysql_num_fields($result); ++$i) {
$table = mysql_field_table($result, $i);
$field = mysql_field_name($result, $i);
echo "$table: $field\n";
}
?>
註釋
Note: 為了保證向下相容性，可以使用下面的別名，但不贊成使用它： mysql_fieldtable()
add a note
User Contributed Notesmysql_field_table
jorge at rhst dot net
29-Jul-2007 09:57
29-Jul-2007 09:57
spam at blondella dot de
03-Oct-2006 11:09
03-Oct-2006 11:09
<?php
/*
this function might help in the case described above :-)
*/
function mysql_field_table_resolve_alias($inQuery,$inResult,$inFieldName) {
$theNameOrAlias = mysql_field_table($inResult,$inFieldName);
//check, if AS syntax is being used
if(ereg(" AS ",$inQuery)) {
//catch words in query
$theWords = explode(" ",ereg_replace(",|\n"," ",$inQuery));
//find the words preceding and following AS
foreach($theWords as $theIndex => $theWord) {
if(trim($theWord) == "AS"
&& isset($theWords[$theIndex-1])
&& isset($theWords[$theIndex+1])
&& $theWords[$theIndex+1] == $theNameOrAlias
) {
$theNameOrAlias = $theWords[$theIndex-1];
break 1;
}
}
}
return $theNameOrAlias;
}
?>
me at thomaskeller dot biz
23-Nov-2005 09:15
23-Nov-2005 09:15
Beware that if you upgrade to MySQL 5 from any earlier version WITHOUT dumping and reloading your data (just by keeping the binary data in MyISAM table files), you might get weird output on the "table" value for mysql_fetch_field and in this function. Weird means that the table name is randomly set or not.
This behaviour seems to popup only if the SQL query contains a ORDER BY clause. A bug is already reported:
http://bugs.mysql.com/bug.php?id=14915
To prevent the issue, dump and reload all participating tables in your query or do
CREATE TABLE tmp SELECT * FROM table;
DROP TABLE table;
ALTER TABLE tmp RENAME table;
on each one via commandline client.
cptnemo
15-Aug-2004 02:18
15-Aug-2004 02:18
When trying to find table names for a (My)SQL query containing 'tablename AS alias', mysql_field_table() only returns the alias as specified in the AS clause, and not the tablename.