Use old ALTER COLUMN syntax for MySQL < 8.0

Follow-up on commit a56568c3f001ec83242a22b0a64568ced30f1171, reworked
from PR #1089.

Fixes #1088

Co-authored-by: Mark Newnham <mark@newnhams.com>

1 files changed, 27 insertions, 1 deletions

diff --git a/datadict/datadict-mysql.inc.php b/datadict/datadict-mysql.inc.php
index 09b27773..6a624288 100644
--- a/datadict/datadict-mysql.inc.php
+++ b/datadict/datadict-mysql.inc.php
@@ -29,7 +29,6 @@ class ADODB2_mysql extends ADODB_DataDict {
 	var $dropTable = 'DROP TABLE IF EXISTS %s'; // requires mysql 3.22 or later
 
 	var $dropIndex = 'DROP INDEX %s ON %s';
-	
 
 	public $blobAllowsNotNull = true;
 	
@@ -213,4 +212,31 @@ class ADODB2_mysql extends ADODB_DataDict {
 
 		return $sql;
 	}
+
+	/**
+	 * Rename one column.
+	 *
+	 * MySQL < 8.0 does not support the standard `RENAME COLUMN` SQL syntax,
+	 * so the $flds parameter must be provided.
+	 *
+	 * @param string $tabname   Table name.
+	 * @param string $oldcolumn Column to be renamed.
+	 * @param string $newcolumn New column name.
+	 * @param string $flds      Complete column definition string like for {@see addColumnSQL};
+	 *                          This is currently only used by MySQL < 8.0. Defaults to ''.
+	 *
+	 * @return array SQL statements.
+	 */
+	function renameColumnSQL($tabname, $oldcolumn, $newcolumn, $flds='')
+	{
+		$version = $this->connection->ServerInfo();
+
+		if (version_compare($version['version'], '8.0', '<')) {
+			$this->renameColumn = 'ALTER TABLE %s CHANGE COLUMN %s %s %s';
+		} else {
+			$flds = '';
+		}
+
+		return parent::renameColumnSQL($tabname, $oldcolumn, $newcolumn, $flds);
+	}
 }