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### What changes were proposed in this pull request? Document TRUNCATE statement in SQL Reference Guide. ### Why are the changes needed? Adding documentation for SQL reference. ### Does this PR introduce any user-facing change? yes Before: There was no documentation for this. After.   ### How was this patch tested? Used jekyll build and serve to verify. Closes #25557 from PavithraRamachandran/truncate_doc. Lead-authored-by: Pavithra Ramachandran <pavi.rams@gmail.com> Co-authored-by: pavithra <pavi.rams@gmail.com> Signed-off-by: Sean Owen <sean.owen@databricks.com>
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| layout | title | displayTitle | license |
|---|---|---|---|
| global | TRUNCATE TABLE | TRUNCATE TABLE | Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You 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. |
Description
The TRUNCATE TABLE statement removes all the rows from a table or partition(s). The table must not be a view
or an external/temporary table. In order to truncate multiple partitions at once, the user can specify the partitions
in partition_spec. If no partition_spec is specified it will remove all partitions in the table.
Syntax
{% highlight sql %} TRUNCATE TABLE table_name [PARTITION partition_spec]; {% endhighlight %}
Parameters
table_name- The name of an existing table.
PARTITION ( partition_spec :[ partition_column = partition_col_value, partition_column = partition_col_value, ...] )- Specifies one or more partition column and value pairs. The partition value is optional.
Examples
{% highlight sql %}
--Create table Student with partition CREATE TABLE Student ( name String, rollno INT) PARTITIONED BY (age int);
SELECT * from Student; +-------+---------+------+--+ | name | rollno | age | +-------+---------+------+--+ | ABC | 1 | 10 | | DEF | 2 | 10 | | XYZ | 3 | 12 | +-------+---------+------+--+
-- Removes all rows from the table in the partion specified TRUNCATE TABLE Student partition(age=10);
--After truncate execution, records belonging to partition age=10 are removed SELECT * from Student; +-------+---------+------+--+ | name | rollno | age | +-------+---------+------+--+ | XYZ | 3 | 12 | +-------+---------+------+--+
-- Removes all rows from the table from all partitions TRUNCATE TABLE Student;
SELECT * from Student; +-------+---------+------+--+ | name | rollno | age | +-------+---------+------+--+ +-------+---------+------+--+ No rows selected
{% endhighlight %}