diff --git a/src/server/db/campaigns.test.ts b/src/server/db/campaigns.test.ts
index 74c475e..f25d59e 100644
--- a/src/server/db/campaigns.test.ts
+++ b/src/server/db/campaigns.test.ts
@@ -102,6 +102,13 @@ describe('updateCampaign', () => {
     const result = await updateCampaign('tenant1', 'uuid-1', {})
     expect(result.ok).toBe(false)
   })
+
+  it('gibt err zurück wenn Kampagne nicht im Draft-Status', async () => {
+    mockClient.query.mockResolvedValueOnce([])
+    const result = await updateCampaign('tenant1', 'uuid-1', { name: 'Neu' })
+    expect(result.ok).toBe(false)
+    if (!result.ok) expect(result.error.message).toContain('Draft-Status')
+  })
 })
 
 describe('updateCampaignStatus', () => {
@@ -119,4 +126,20 @@ describe('updateCampaignStatus', () => {
     const result = await updateCampaignStatus('tenant1', 'uuid-1', 'sent')
     expect(result.ok).toBe(false)
   })
+
+  it('setzt scheduledAt ohne cron_expression zu überschreiben', async () => {
+    const scheduled = new Date('2026-05-01T09:00:00Z')
+    mockClient.query.mockResolvedValueOnce([{ ...mockRow, status: 'scheduled', scheduled_at: scheduled }])
+    const result = await updateCampaignStatus('tenant1', 'uuid-1', 'scheduled', { scheduledAt: scheduled })
+    expect(result.ok).toBe(true)
+    expect(mockClient.query).toHaveBeenCalledWith(
+      expect.stringContaining('scheduled_at'),
+      expect.arrayContaining([scheduled])
+    )
+    // cron_expression darf NICHT im Query sein
+    expect(mockClient.query).not.toHaveBeenCalledWith(
+      expect.stringContaining('cron_expression'),
+      expect.anything()
+    )
+  })
 })
diff --git a/src/server/db/campaigns.ts b/src/server/db/campaigns.ts
index 67bdfac..e723fff 100644
--- a/src/server/db/campaigns.ts
+++ b/src/server/db/campaigns.ts
@@ -99,12 +99,25 @@ export async function updateCampaignStatus(
   status: CampaignStatus,
   extra?: { scheduledAt?: Date; cronExpression?: string }
 ): Promise<Result<Campaign>> {
+  const fields: string[] = ['status = $1']
+  const values: unknown[] = [status]
+  let idx = 2
+
+  if (extra?.scheduledAt !== undefined) {
+    fields.push(`scheduled_at = $${idx++}`)
+    values.push(extra.scheduledAt)
+  }
+  if (extra?.cronExpression !== undefined) {
+    fields.push(`cron_expression = $${idx++}`)
+    values.push(extra.cronExpression)
+  }
+
+  values.push(id)
   try {
     const rows = await withTenant(tenantId, (client) =>
       client.query(
-        `UPDATE campaigns SET status = $1, scheduled_at = $2, cron_expression = $3
-         WHERE id = $4 RETURNING *`,
-        [status, extra?.scheduledAt ?? null, extra?.cronExpression ?? null, id]
+        `UPDATE campaigns SET ${fields.join(', ')} WHERE id = $${idx} RETURNING *`,
+        values
       )
     )
     if (rows.length === 0) return err(new Error('Kampagne nicht gefunden'))