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### What changes were proposed in this pull request? Document CREATE TABLE 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. ### How was this patch tested? Used jekyll build and serve to verify. Closes #26759 from PavithraRamachandran/create_doc. Authored-by: Pavithra Ramachandran <pavi.rams@gmail.com> Signed-off-by: Sean Owen <srowen@gmail.com>
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| layout | title | displayTitle | license |
|---|---|---|---|
| global | CREATE DATASOURCE TABLE | CREATE DATASOURCE 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 CREATE TABLE statement defines a new table using a Data Source.
Syntax
{% highlight sql %} CREATE TABLE [ IF NOT EXISTS ] table_identifier [ ( col_name1 col_type1 [ COMMENT col_comment1 ], ... ) ] USING data_source [ OPTIONS ( key1=val1, key2=val2, ... ) ] [ PARTITIONED BY ( col_name1, col_name2, ... ) ] [ CLUSTERED BY ( col_name3, col_name4, ... ) [ SORTED BY ( col_name [ ASC | DESC ], ... ) ] INTO num_buckets BUCKETS ] [ LOCATION path ] [ COMMENT table_comment ] [ TBLPROPERTIES ( key1=val1, key2=val2, ... ) ] [ AS select_statement ] {% endhighlight %}
Parameters
table_identifier-
Specifies a table name, which may be optionally qualified with a database name.
Syntax:[ database_name. ] table_name
USING data_source- Data Source is the input format used to create the table. Data source can be CSV, TXT, ORC, JDBC, PARQUET, etc.
PARTITIONED BY- Partitions are created on the table, based on the columns specified.
CLUSTERED BY-
Partitions created on the table will be bucketed into fixed buckets based on the column specified for bucketing.
NOTE:Bucketing is an optimization technique that uses buckets (and bucketing columns) to determine data partitioning and avoid data shuffle.
SORTED BY- Determines the order in which the data is stored in buckets. Default is Ascending order.
LOCATION- Path to the directory where table data is stored, which could be a path on distributed storage like HDFS, etc.
COMMENT- Table comments are added.
TBLPROPERTIES- Table properties that have to be set are specified, such as `created.by.user`, `owner`, etc.
AS select_statement- The table is populated using the data from the select statement.
Examples
{% highlight sql %}
--Using data source CREATE TABLE Student (Id INT,name STRING ,age INT) USING CSV;
--Using data from another table CREATE TABLE StudentInfo AS SELECT * FROM Student;
--Partitioned and bucketed CREATE TABLE Student (Id INT,name STRING ,age INT) USING CSV PARTITIONED BY (age) CLUSTERED BY (Id) INTO 4 buckets;
{% endhighlight %}