Add tagWith() method to QueryBuilder for SQL comment tags

This implementation adds a tagWith() method to the QueryBuilder class,
which allows adding SQL comment tags to generated queries for debugging,
logging, and analysis purposes.

Author: jdecool

src/Query/QueryBuilder.php

@@ -175,6 +175,13 @@ class QueryBuilder
      */
     private ?QueryCacheProfile $resultCacheProfile = null;
 
+    /**
+     * The comment tags to be added to the SQL query.
+     *
+     * @var string[]
+     */
+    private array $commentTags = [];
+
     /**
      * Initializes a new <tt>QueryBuilder</tt>.
      *
@@ -358,13 +365,19 @@ public function executeStatement(): int|string
      */
     public function getSQL(): string
     {
-        return $this->sql ??= match ($this->type) {
+        if ($this->sql !== null) {
+            return $this->sql;
+        }
+
+        $sql = match ($this->type) {
             QueryType::INSERT => $this->getSQLForInsert(),
             QueryType::DELETE => $this->getSQLForDelete(),
             QueryType::UPDATE => $this->getSQLForUpdate(),
             QueryType::SELECT => $this->getSQLForSelect(),
             QueryType::UNION  => $this->getSQLForUnion(),
         };
+
+        return $this->sql = $this->addCommentTagsToSQL($sql);
     }
 
     /**
@@ -1661,4 +1674,52 @@ public function disableResultCache(): self
 
         return $this;
     }
+
+    /**
+     * Adds a comment tag to the SQL query.
+     *
+     * This method adds a SQL comment that will be prepended to the generated SQL query.
+     * Multiple tags can be added and will appear in the order they were added.
+     *
+     * <code>
+     *     $qb = $conn->createQueryBuilder()
+     *         ->select('u.id', 'u.name')
+     *         ->from('users', 'u')
+     *         ->tagWith('This is a custom tag')
+     *         ->tagWith('Another tag');
+     * </code>
+     *
+     * @param string $tag The comment tag to add to the query.
+     *
+     * @return $this This QueryBuilder instance.
+     */
+    public function tagWith(string $tag): self
+    {
+        $this->commentTags[] = $tag;
+
+        $this->sql = null;
+
+        return $this;
+    }
+
+    /**
+      * Adds comment tags to the SQL query.
+      *
+      * @param string $sql The SQL query to add tags to.
+      *
+      * @return string The SQL query with comment tags prepended.
+      */
+    private function addCommentTagsToSQL(string $sql): string
+    {
+        if (count($this->commentTags) === 0) {
+            return $sql;
+        }
+
+        $commentLines = [];
+        foreach ($this->commentTags as $tag) {
+            $commentLines[] = '-- ' . $tag;
+        }
+
+        return implode("\n", $commentLines) . "\n\n" . $sql;
+    }
 }

tests/Query/QueryBuilderTest.php

@@ -1546,4 +1546,124 @@ public function testUnionAndOrderByReturnsUnionQueryWithOrderBy(): void
             $qb->getSQL(),
         );
     }
+
+    public function testTagWithSingleTag(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->select('u.id', 'u.name')
+            ->from('users', 'u')
+            ->tagWith('This is a test query');
+
+        self::assertEquals(
+            "-- This is a test query\n\nSELECT u.id, u.name FROM users u",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithMultipleTags(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->select('u.id', 'u.name')
+            ->from('users', 'u')
+            ->tagWith('First tag')
+            ->tagWith('Second tag')
+            ->tagWith('Third tag');
+
+        self::assertEquals(
+            "-- First tag\n-- Second tag\n-- Third tag\n\nSELECT u.id, u.name FROM users u",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithInsertQuery(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->insert('users')
+            ->values(['name' => '?', 'email' => '?'])
+            ->tagWith('Insert operation');
+
+        self::assertEquals(
+            "-- Insert operation\n\nINSERT INTO users (name, email) VALUES(?, ?)",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithUpdateQuery(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->update('users')
+            ->set('name', '?')
+            ->where('id = ?')
+            ->tagWith('Update operation');
+
+        self::assertEquals(
+            "-- Update operation\n\nUPDATE users SET name = ? WHERE id = ?",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithDeleteQuery(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->delete('users')
+            ->where('id = ?')
+            ->tagWith('Delete operation');
+
+        self::assertEquals(
+        "-- Delete operation\n\nDELETE FROM users WHERE id = ?", $qb->getSQL());
+    }
+
+    public function testTagWithNoTags(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->select('u.id', 'u.name')
+            ->from('users', 'u');
+
+        self::assertEquals(
+            "SELECT u.id, u.name FROM users u",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithMethodChaining(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->select('u.id')
+            ->from('users', 'u')
+            ->tagWith('Tag 1')
+            ->where('u.id = ?')
+            ->tagWith('Tag 2')
+            ->orderBy('u.name');
+
+        self::assertEquals(
+            "-- Tag 1\n-- Tag 2\n\nSELECT u.id FROM users u WHERE u.id = ? ORDER BY u.name",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithEmptyTag(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->select('u.id')
+            ->from('users', 'u')
+            ->tagWith('');
+
+        self::assertEquals(
+            "-- \n\nSELECT u.id FROM users u",
+            $qb->getSQL(),
+        );
+    }
+
+    public function testTagWithSpecialCharacters(): void
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->select('u.id')
+            ->from('users', 'u')
+            ->tagWith("Tag with 'quotes' and \"double quotes\"");
+
+        self::assertEquals(
+            "-- Tag with 'quotes' and \"double quotes\"\n\nSELECT u.id FROM users u",
+            $qb->getSQL(),
+        );
+    }
 }