[SPARK-28787][DOC][SQL] Document LOAD DATA statement in SQL Reference
### What changes were proposed in this pull request? Document LOAD DATA statement in SQL Reference ### Why are the changes needed? To complete the SQL Reference ### Does this PR introduce any user-facing change? Yes ### How was this patch tested? Tested using jykyll build --serve Here are the screen shots:    Closes #25522 from huaxingao/spark-28787. Authored-by: Huaxin Gao <huaxing@us.ibm.com> Signed-off-by: Sean Owen <sean.owen@databricks.com>
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Huaxin Gao
Sean Owen
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---
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layout: global
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title: LOAD
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displayTitle: LOAD
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title: LOAD DATA
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displayTitle: LOAD DATA
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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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@ -19,4 +19,101 @@ license: |
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limitations under the License.
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---
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**This page is under construction**
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### Description
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`LOAD DATA` statement loads the data into a table from the user specified directory or file. If a directory is specified then all the files from the directory are loaded. If a file is specified then only the single file is loaded. Additionally the `LOAD DATA` statement takes an optional partition specification. When a partition is specified, the data files (when input source is a directory) or the single file (when input source is a file) are loaded into the partition of the target table.
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### Syntax
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{% highlight sql %}
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LOAD DATA [ LOCAL ] INPATH path [ OVERWRITE ] INTO TABLE table_name
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[ PARTITION ( partition_col_name = partition_col_val [ , ... ] ) ]
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{% endhighlight %}
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### Parameters
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<dl>
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<dt><code><em>path</em></code></dt>
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<dd>Path of the file system. It can be either an absolute or a relative path.</dd>
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</dl>
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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_col_name = partition_col_val [ , ... ] )</em></code></dt>
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<dd>Specifies one or more partition column and value pairs.</dd>
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</dl>
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<dl>
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<dt><code><em>LOCAL</em></code></dt>
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<dd>If specified, it causes the <code>INPATH</code> to be resolved against the local file system, instead of the default file system, which is typically a distributed storage.</dd>
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</dl>
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<dl>
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<dt><code><em>OVERWRITE</em></code></dt>
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<dd>By default, new data is appended to the table. If <code>OVERWRITE</code> is used, the table is instead overwritten with new data.</dd>
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</dl>
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### Examples
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{% highlight sql %}
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-- Example without partition specification.
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-- Assuming the students table has already been created and populated.
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SELECT * FROM students;
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+ -------------- + ------------------------------ + -------------- +
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| name | address | student_id |
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+ -------------- + ------------------------------ + -------------- +
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| Amy Smith | 123 Park Ave, San Jose | 111111 |
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+ -------------- + ------------------------------ + -------------- +
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CREATE TABLE test_load (name VARCHAR(64), address VARCHAR(64), student_id INT);
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-- Assuming the students table is in '/user/hive/warehouse/'
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LOAD DATA LOCAL INPATH '/user/hive/warehouse/students' OVERWRITE INTO TABLE test_load;
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SELECT * FROM test_load;
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+ -------------- + ------------------------------ + -------------- +
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| name | address | student_id |
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+ -------------- + ------------------------------ + -------------- +
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| Amy Smith | 123 Park Ave, San Jose | 111111 |
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+ -------------- + ------------------------------ + -------------- +
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-- Example with partition specification.
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CREATE TABLE test_partition (c1 INT, c2 INT, c3 INT) USING HIVE PARTITIONED BY (c2, c3);
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INSERT INTO test_partition PARTITION (c2 = 2, c3 = 3) VALUES (1);
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INSERT INTO test_partition PARTITION (c2 = 5, c3 = 6) VALUES (4);
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INSERT INTO test_partition PARTITION (c2 = 8, c3 = 9) VALUES (7);
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SELECT * FROM test_partition;
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+ ------- + ------- + ----- +
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| c1 | c2 | c3 |
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+ ------- + --------------- +
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| 1 | 2 | 3 |
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+ ------- + ------- + ----- +
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| 4 | 5 | 6 |
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+ ------- + ------- + ----- +
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| 7 | 8 | 9 |
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+ ------- + ------- + ----- +
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CREATE TABLE test_load_partition (c1 INT, c2 INT, c3 INT) USING HIVE PARTITIONED BY (c2, c3);
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-- Assuming the test_partition table is in '/user/hive/warehouse/'
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LOAD DATA LOCAL INPATH '/user/hive/warehouse/test_partition/c2=2/c3=3'
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OVERWRITE INTO TABLE test_load_partition PARTITION (c2=2, c3=3);
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SELECT * FROM test_load_partition;
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+ ------- + ------- + ----- +
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| c1 | c2 | c3 |
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+ ------- + --------------- +
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| 1 | 2 | 3 |
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+ ------- + ------- + ----- +
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{% endhighlight %}
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