left.sqlx

config { hasOutput: true }
/*
 * Copyright 2019 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

CREATE OR REPLACE FUNCTION ${self()}(string_expr STRING, length_expr INT64) AS (
  CASE
    WHEN length_expr < 0 THEN ERROR('The length argument to LEFT must be a positive integer!')
    ELSE SUBSTR(string_expr, 1, length_expr)
  END
);