feat(UNIX_TIMESTAMP): add basic support for UNIX_TIMESTAMP function

Author: rtm-ctrlz

src/Processor/Expression/FunctionEvaluator.php

@@ -71,6 +71,8 @@ public static function evaluate(
                 return self::sqlBinary($conn, $scope, $expr, $row, $result);
             case 'FROM_UNIXTIME':
                 return self::sqlFromUnixtime($conn, $scope, $expr, $row, $result);
+            case 'UNIX_TIMESTAMP':
+                return self::sqlUnitTimestamp($conn, $scope, $expr, $row, $result);
             case 'GREATEST':
                 return self::sqlGreatest($conn, $scope, $expr, $row, $result);
             case 'VALUES':
@@ -845,6 +847,30 @@ private static function sqlFromUnixtime(
         return \date('Y-m-d H:i:s', (int) $column);
     }
 
+    /**
+     * @param array<string, mixed> $row
+     */
+    private static function sqlUnixTimestamp(
+        FakePdoInterface $conn,
+        Scope $scope,
+        FunctionExpression $expr,
+        array $row,
+        QueryResult $result
+    ) : int {
+        $args = $expr->args;
+
+        if (\count($args) === 0) {
+            return \time();
+        }
+
+        if (\count($args) > 1) {
+            throw new ProcessorException("MySQL UNIX_TIMESTAPM() SQLFake only implemented for 0 or 1 argument");
+        }
+
+        $column = Evaluator::evaluate($conn, $scope, $args[0], $row, $result);
+        return \strtotime($column);
+    }
+
     /**
      * @param array<string, mixed> $row
      *