b48ef7a9fb
### 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. ![image (4)](https://user-images.githubusercontent.com/51401130/64956929-5e057780-d8a9-11e9-89a3-2d02c942b9ad.png) ![image (5)](https://user-images.githubusercontent.com/51401130/64956942-61006800-d8a9-11e9-9767-6164eabfdc2c.png) ### 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>
87 lines
2.7 KiB
Markdown
87 lines
2.7 KiB
Markdown
---
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layout: global
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title: TRUNCATE TABLE
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displayTitle: TRUNCATE TABLE
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license: |
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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---
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### Description
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The `TRUNCATE TABLE` statement removes all the rows from a table or partition(s). The table must not be a view
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or an external/temporary table. In order to truncate multiple partitions at once, the user can specify the partitions
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in `partition_spec`. If no `partition_spec` is specified it will remove all partitions in the table.
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### Syntax
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{% highlight sql %}
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TRUNCATE TABLE table_name [PARTITION partition_spec];
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{% endhighlight %}
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### Parameters
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<dl>
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<dt><code><em>table_name</em></code></dt>
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<dd>The name of an existing table.</dd>
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</dl>
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<dl>
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<dt><code><em>PARTITION ( partition_spec :[ partition_column = partition_col_value, partition_column = partition_col_value, ...] )</em></code></dt>
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<dd>Specifies one or more partition column and value pairs. The partition value is optional.</dd>
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</dl>
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### Examples
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{% highlight sql %}
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--Create table Student with partition
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CREATE TABLE Student ( name String, rollno INT) PARTITIONED BY (age int);
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SELECT * from Student;
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+-------+---------+------+--+
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| name | rollno | age |
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+-------+---------+------+--+
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| ABC | 1 | 10 |
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| DEF | 2 | 10 |
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| XYZ | 3 | 12 |
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+-------+---------+------+--+
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-- Removes all rows from the table in the partion specified
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TRUNCATE TABLE Student partition(age=10);
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--After truncate execution, records belonging to partition age=10 are removed
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SELECT * from Student;
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+-------+---------+------+--+
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| name | rollno | age |
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+-------+---------+------+--+
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| XYZ | 3 | 12 |
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+-------+---------+------+--+
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-- Removes all rows from the table from all partitions
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TRUNCATE TABLE Student;
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SELECT * from Student;
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+-------+---------+------+--+
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| name | rollno | age |
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+-------+---------+------+--+
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+-------+---------+------+--+
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No rows selected
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{% endhighlight %}
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### Related Statements
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- [DROP TABLE](sql-ref-syntax-ddl-drop-table.html)
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- [ALTER TABLE](sql-ref-syntax-ddl-alter-tabley.html)
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