Enhance SQL script for timewish table; implement conditional column addition for start_date and end_date to ensure compatibility with existing schema and prevent errors if columns already exist.

backend/setup-timewish-complete.sql

@@ -2,9 +2,38 @@
 -- Führe dieses Script in deiner stechuhr2 Datenbank aus
 
 -- Schritt 1: Tabelle anpassen (Spalten hinzufügen)
-ALTER TABLE `timewish` 
-  ADD COLUMN IF NOT EXISTS `start_date` DATE DEFAULT '2023-01-01' COMMENT 'Ab welchem Datum gilt dieser Timewish' AFTER `end_time`,
-  ADD COLUMN IF NOT EXISTS `end_date` DATE DEFAULT NULL COMMENT 'Bis welchem Datum gilt dieser Timewish (NULL = bis heute)' AFTER `start_date`;
+-- Spalten einzeln hinzufügen (kompatibel mit MySQL 8.0)
+-- Ignoriert Fehler falls Spalten bereits existieren
+
+-- start_date Spalte (ignoriert Fehler falls vorhanden)
+SET @sql = (
+    SELECT IF(
+        COUNT(*) = 0,
+        'ALTER TABLE `timewish` ADD COLUMN `start_date` DATE DEFAULT ''2023-01-01'' COMMENT ''Ab welchem Datum gilt dieser Timewish'' AFTER `end_time`;',
+        'SELECT ''Spalte start_date existiert bereits'' AS Info;'
+    ) FROM information_schema.COLUMNS 
+    WHERE TABLE_SCHEMA = DATABASE() 
+    AND TABLE_NAME = 'timewish' 
+    AND COLUMN_NAME = 'start_date'
+);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
+
+-- end_date Spalte (ignoriert Fehler falls vorhanden)
+SET @sql = (
+    SELECT IF(
+        COUNT(*) = 0,
+        'ALTER TABLE `timewish` ADD COLUMN `end_date` DATE DEFAULT NULL COMMENT ''Bis welchem Datum gilt dieser Timewish (NULL = bis heute)'' AFTER `start_date`;',
+        'SELECT ''Spalte end_date existiert bereits'' AS Info;'
+    ) FROM information_schema.COLUMNS 
+    WHERE TABLE_SCHEMA = DATABASE() 
+    AND TABLE_NAME = 'timewish' 
+    AND COLUMN_NAME = 'end_date'
+);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
 
 -- Schritt 2: Bestehende Einträge löschen (falls vorhanden)
 DELETE FROM `timewish` WHERE user_id = 1;