diff --git a/src/Audit/Adapter/ClickHouse.php b/src/Audit/Adapter/ClickHouse.php
index 0d598d5..1ebd7b7 100644
--- a/src/Audit/Adapter/ClickHouse.php
+++ b/src/Audit/Adapter/ClickHouse.php
@@ -42,7 +42,7 @@ class ClickHouse extends SQL
 
     protected string $namespace = '';
 
-    protected ?int $tenant = null;
+    protected int|string|null $tenant = null;
 
     protected bool $sharedTables = false;
 
@@ -208,10 +208,10 @@ public function getNamespace(): string
      * Set the tenant ID for multi-tenant support.
      * Tenant is used to isolate audit logs by tenant.
      *
-     * @param int|null $tenant
+     * @param int|string|null $tenant
      * @return self
      */
-    public function setTenant(?int $tenant): self
+    public function setTenant(int|string|null $tenant): self
     {
         $this->tenant = $tenant;
         return $this;
@@ -220,9 +220,9 @@ public function setTenant(?int $tenant): self
     /**
      * Get the tenant ID.
      *
-     * @return int|null
+     * @return int|string|null
      */
-    public function getTenant(): ?int
+    public function getTenant(): int|string|null
     {
         return $this->tenant;
     }
@@ -631,7 +631,7 @@ public function setup(): void
 
         // Add tenant column only if tables are shared across tenants
         if ($this->sharedTables) {
-            $columns[] = 'tenant Nullable(UInt64)';  // Supports 11-digit MySQL auto-increment IDs
+            $columns[] = 'tenant Nullable(String)';
         }
 
         // Build indexes from base adapter schema
@@ -799,7 +799,7 @@ public function getById(string $id): ?Log
             FORMAT JSON
         ";
 
-        $result = $this->query($sql, ['id' => $id]);
+        $result = $this->query($sql, array_merge(['id' => $id], $this->getTenantParams()));
         $logs = $this->parseJsonResults($result);
 
         return $logs[0] ?? null;
@@ -850,7 +850,7 @@ public function find(array $queries = []): array
             FORMAT JSON
         ";
 
-        $result = $this->query($sql, $parsed['params']);
+        $result = $this->query($sql, array_merge($parsed['params'], $this->getTenantParams()));
         return $this->parseJsonResults($result);
     }
 
@@ -890,7 +890,7 @@ public function count(array $queries = []): int
             FORMAT TabSeparated
         ";
 
-        $result = $this->query($sql, $params);
+        $result = $this->query($sql, array_merge($params, $this->getTenantParams()));
         $trimmed = trim($result);
 
         return $trimmed !== '' ? (int) $trimmed : 0;
@@ -1197,11 +1197,13 @@ private function parseJsonResults(string $result): array
                         $document[$columnName] = $value ?? [];
                     }
                 } elseif ($columnName === 'tenant') {
-                    // Parse tenant as integer or null
+                    // Parse tenant as int, string, or null
                     if ($value === null || $value === '') {
                         $document[$columnName] = null;
                     } elseif (is_numeric($value)) {
                         $document[$columnName] = (int) $value;
+                    } elseif (is_scalar($value)) {
+                        $document[$columnName] = (string) $value;
                     } else {
                         $document[$columnName] = null;
                     }
@@ -1279,7 +1281,21 @@ private function getTenantFilter(): string
         }
 
         $escapedTenant = $this->escapeIdentifier('tenant');
-        return " AND {$escapedTenant} = {$this->tenant}";
+        return " AND {$escapedTenant} = {_tenant:String}";
+    }
+
+    /**
+     * Get query parameters for tenant filtering.
+     *
+     * @return array<string, mixed>
+     */
+    private function getTenantParams(): array
+    {
+        if (!$this->sharedTables || $this->tenant === null) {
+            return [];
+        }
+
+        return ['_tenant' => (string) $this->tenant];
     }
 
     /**
@@ -1570,7 +1586,7 @@ public function cleanup(\DateTime $datetime): bool
             WHERE time < {datetime:String}{$tenantFilter}
         ";
 
-        $this->query($sql, ['datetime' => $datetimeString]);
+        $this->query($sql, array_merge(['datetime' => $datetimeString], $this->getTenantParams()));
 
         return true;
     }
diff --git a/src/Audit/Log.php b/src/Audit/Log.php
index ffbf197..6708008 100644
--- a/src/Audit/Log.php
+++ b/src/Audit/Log.php
@@ -126,9 +126,9 @@ public function getData(): array
     /**
      * Get the tenant ID (for multi-tenant setups).
      *
-     * @return int|null
+     * @return int|string|null
      */
-    public function getTenant(): ?int
+    public function getTenant(): int|string|null
     {
         $tenant = $this->getAttribute('tenant');
 
@@ -140,8 +140,8 @@ public function getTenant(): ?int
             return $tenant;
         }
 
-        if (is_numeric($tenant)) {
-            return (int) $tenant;
+        if (is_string($tenant)) {
+            return $tenant;
         }
 
         return null;
diff --git a/tests/Audit/Adapter/ClickHouseTest.php b/tests/Audit/Adapter/ClickHouseTest.php
index 1374c71..f252833 100644
--- a/tests/Audit/Adapter/ClickHouseTest.php
+++ b/tests/Audit/Adapter/ClickHouseTest.php
@@ -299,11 +299,15 @@ public function testSharedTablesConfiguration(): void
         $this->assertInstanceOf(ClickHouse::class, $result);
         $this->assertTrue($adapter->isSharedTables());
 
-        // Test setting tenant
+        // Test setting tenant to int
         $result2 = $adapter->setTenant(12345);
         $this->assertInstanceOf(ClickHouse::class, $result2);
         $this->assertEquals(12345, $adapter->getTenant());
 
+        // Test setting tenant to string
+        $adapter->setTenant('tenant_abc');
+        $this->assertSame('tenant_abc', $adapter->getTenant());
+
         // Test setting tenant to null
         $adapter->setTenant(null);
         $this->assertNull($adapter->getTenant());