PHPMyAdmin中使用sql-parser進行SQL語法分析

寫SQL對於PHP來說是常的事，那麼如何對SQL語句進行分析來最佳化SQL呢？ sql-parser就提供了這樣的功能，讓我們一起來看看。

phpMyAdmin是一款基於Web端運行的開源資料庫管理工具，支援管理MySQL和MariaDB兩種資料庫。 phpMyAdmin的程式主要使用php和javascript開發，它的安裝使用都比較簡單且已經有許多相關介紹不再重複，今天要介紹的是原始碼中的一個核心元件sql-parser。

sql-parser簡介

sql-parser元件的主要用途是對SQL語句進行詞法分析、語法分析，繼而可以實現對SQL語句的解構、加工、替換、再組裝等需求，另外也可以對SQL進行highlight等處理。 sql-parser由純PHP語言實現，同時也是整個phpMyAdmin原始碼中少數的程式碼架構較為清晰且符合目前PHP界PSR標準規範的模組。

sql-parser元件安裝

需事先安裝好php，git客戶端，以及composer php套件管理工具

margin@margin-MB1:~/tmp$ sudo git clone https://github.com/phpmyadmin/sql-parser.git
margin@margin-MB1:~/tmp$ cd sql-parser && sudo composer install

元件安裝完畢，下面介紹具體的呼叫

解析普通語句

require_once '../sql-parser/vendor/autoload.php';
use SqlParser\Parser;
$query = 'SELECT * FROM t1 LEFT JOIN (t2, t3, t4) '
    . 'ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)';
$parser = new Parser($query);
$stmt = $parser->statements[0];
echo json_encode($stmt);

運行結果中$parser變數是一個大對象，裡面儲存有對$query語句的詞法分析結果$query->list，語法分析結果$query- statements，以及錯誤訊息等。
其中$query-statements的結構如下：

{"expr":
[{"database":null,"table":null,"column":null,"expr":"*","alias":null,"function":n
ull,"subquery":null}],"from":
[{"database":null,"table":"t1","column":null,"expr":"t1","alias":null,"function":
null,"subquery":null}],"partition":null,"where":null,"group":null,"having":null,"
order":null,"limit":null,"procedure":null,"into":null,"join":
[{"type":"LEFT","expr":{"database":null,"table":null,"column":null,"expr":"(t2, 
t3, t4)","alias":null,"function":null,"subquery":null},"on":[{"identifiers":
["t2","a","t1"],"isOperator":false,"expr":"(t2.a=t1.a"},{"identifiers":
[],"isOperator":true,"expr":"AND"},{"identifiers":
["t3","b","t1"],"isOperator":false,"expr":"t3.b=t1.b"},{"identifiers":
[],"isOperator":true,"expr":"AND"},{"identifiers":
["t4","c","t1"],"isOperator":false,"expr":"t4.c=t1.c)"}],"using":null}],"union":
[],"options":{"options":[]},"first":0,"last":50}

 

#解析交易

require_once '../sql-parser/vendor/autoload.php';
use SqlParser\Parser;
$query = 'START TRANSACTION;' .
    'SELECT @A:=SUM(salary) FROM table1 WHERE type=1;' .
    'UPDATE table2 SET summary=@A WHERE type=1;' .
    'COMMIT;';
$parser = new Parser($query);
$stmt = $parser->statements[0];
echo json_encode($stmt);

輸出結果：

{"type":1,"statements":[{"expr":
[{"database":null,"table":null,"column":null,"expr":"@A:=SUM(salary)","alias":nul
l,"function":"SUM","subquery":null}],"from":
[{"database":null,"table":"table1","column":null,"expr":"table1","alias":null,"fu
nction":null,"subquery":null}],"partition":null,"where":[{"identifiers":
["type"],"isOperator":false,"expr":"type=1"}],"group":null,"having":null,"order":
null,"limit":null,"procedure":null,"into":null,"join":null,"union":[],"options":
{"options":[]},"first":1,"last":19},{"tables":
[{"database":null,"table":"table2","column":null,"expr":"table2","alias":null,"fu
nction":null,"subquery":null}],"set":[{"column":"summary","value":"@A"}],"where":
[{"identifiers":
["type"],"isOperator":false,"expr":"type=1"}],"order":null,"limit":null,"options"
:{"options":[]},"first":20,"last":35}],"end":
{"type":2,"statements":null,"end":null,"options":{"options":
{"1":"COMMIT"}},"first":36,"last":37},"options":{"options":{"1":"START 
TRANSACTION"}},"first":0,"last":0}

除以上兩種語句之外，sql-parser幾乎支援解析預存程序等幾乎所有MySQL語法，不再一一舉例。以下是其SQL建構器的用法舉例。

組裝SQL語句

組裝select語句：

require_once '../sql-parser/vendor/autoload.php';
use SqlParser\Components\OptionsArray;
use SqlParser\Components\Expression;
use SqlParser\Components\Condition;
use SqlParser\Components\Limit;
use SqlParser\Statements\SelectStatement;
$stmt = new SelectStatement();
$stmt->options = new OptionsArray(array('DISTINCT'));
$stmt->expr[] = new Expression('sakila', 'film', 'film_id', 'fid');
$stmt->expr[] = new Expression('COUNT(film_id)');
$stmt->from[] = new Expression('', 'film', '');
$stmt->from[] = new Expression('', 'actor', '');
$stmt->where[] = new Condition('film_id > 10');
$stmt->where[] = new Condition('OR');
$stmt->where[] = new Condition('actor.age > 25');
$stmt->limit = new Limit(1, 10);
var_dump($stmt->build());

輸出結果：

margin@margin-MB1:~/code/parserTest$ php build.php 
string(137) "SELECT DISTINCT `sakila`.`film`.`film_id` AS `fid`, COUNT(film_id) 
FROM `film`, `actor` WHERE film_id > 10 OR actor.age > 25 LIMIT 10, 1 "

組裝觸發器語句：

require_once '../sql-parser/vendor/autoload.php';
use SqlParser\Components\Expression;
use SqlParser\Components\OptionsArray;
use SqlParser\Statements\CreateStatement;
$stmt = new CreateStatement();
$stmt->options = new OptionsArray(array('TRIGGER'));
$stmt->name = new Expression('ins_sum');
$stmt->entityOptions = new OptionsArray(array('BEFORE', 'INSERT'));
$stmt->table = new Expression('account');
$stmt->body = 'SET @sum = @sum + NEW.amount';
var_dump($stmt->build());

 

輸出結果：

margin@margin-MB1:~/code/parserTest$ php build.php 
string(89) "CREATE TRIGGER ins_sum BEFORE INSERT ON account FOR EACH ROW SET @sum 
= @sum + NEW.amount"

SQL再加工

多條語句一起處理：

require_once '../sql-parser/vendor/autoload.php';
use SqlParser\Parser;
use SqlParser\Components\Expression;
$query  = <<<str id="3" from="" change="" $statement_0="$parser-" 处理第一条语句="" parser($query);="" $parser="new" str;="" where="" tbl3="" *="" select="" null;="" not="" unsigned="" )="" 10="" int(="" `field_2`="" `field_1`="" `tbl`="" table="" alter="" auto_increment;="" null="" `uid`="">statements[0];
$statement_0->table  = new Expression(
    &#39;db2&#39;, &#39;tb2&#39;, &#39;&#39;
);
var_dump($statement_0->build());
//处理第二条语句
$statement_1 = $parser->statements[1];
$statement_1->table  = new Expression(
    &#39;db3&#39;, &#39;tb3&#39;, &#39;&#39;
);
var_dump($statement_1->build());</str>

輸出結果：

margin@margin-MB1:~/code/parserTest$ php build.php 
string(85) "ALTER TABLE `db2`.`tb2` CHANGE `uid` `uid` INT( 10 ) UNSIGNED NOT 
NULL AUTO_INCREMENT"
string(78) "ALTER TABLE `db3`.`tb3` CHANGE `field_1` `field_2` INT( 10 ) UNSIGNED 
NOT NULL"

以上是sql-parser元件一些基本的用法範例，phpMyAdmin的sql-parser元件功能比較豐富和完備，本文限了篇幅不能詳盡，有興趣的讀者可以透過閱讀原始碼來了解更多進階的用法。

相關推薦：

關於MySQL 最佳化的一些動作

mysql 最佳化（3）叢集索引和非叢集索引

MySql Sql 最佳化技巧的圖文程式碼詳細介紹

#

以上是PHPMyAdmin中使用sql-parser進行SQL語法分析的詳細內容。更多資訊請關注PHP中文網其他相關文章！