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cw_array_stable_distinct.sqlx
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config { hasOutput: true }
/*
* Copyright 2023 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.
*/
/*
* Removes duplicates from ARRAY while preserving the elements ordering.
* Duplicate with the lowest index is retained, others are discarded.
*/
CREATE OR REPLACE FUNCTION ${self()}(arr ANY TYPE)
OPTIONS(description="""Removes duplicates from ARRAY while preserving the elements ordering.
Duplicate with the lowest index is retained, others are discarded.
""")
AS (
ARRAY(SELECT el FROM (SELECT el, MIN(idx) as idx FROM UNNEST(arr) as el WITH OFFSET AS idx GROUP BY el) ORDER BY idx)
);