2410a45703
### What changes were proposed in this pull request? SQL Reference cleanup ### Why are the changes needed? To complete SQL Reference ### Does this PR introduce _any_ user-facing change? updated sql-ref-syntax-qry.html before <img width="1100" alt="Screen Shot 2020-04-29 at 11 08 25 PM" src="https://user-images.githubusercontent.com/13592258/80677799-70b27280-8a6e-11ea-8e3f-a768f29d0377.png"> after <img width="1100" alt="Screen Shot 2020-04-29 at 11 05 55 PM" src="https://user-images.githubusercontent.com/13592258/80677803-74de9000-8a6e-11ea-880c-aa05c53254a6.png"> ### How was this patch tested? Manually build and check Closes #28417 from huaxingao/cleanup. Authored-by: Huaxin Gao <huaxing@us.ibm.com> Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
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| layout | title | displayTitle | license |
|---|---|---|---|
| global | DROP TABLE | DROP 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
DROP TABLE deletes the table and removes the directory associated with the table from the file system
if the table is not EXTERNAL table. If the table is not present it throws an exception.
In case of an external table, only the associated metadata information is removed from the metastore database.
Syntax
{% highlight sql %} DROP TABLE [ IF EXISTS ] table_identifier {% endhighlight %}
Parameter
IF EXISTS- If specified, no exception is thrown when the table does not exists.
table_identifier-
Specifies the table name to be dropped. The table name may be optionally qualified with a database name.
Syntax:[ database_name. ] table_name
Examples
{% highlight sql %}
-- Assumes a table named employeetable exists.
DROP TABLE employeetable;
-- Assumes a table named employeetable exists in the userdb database
DROP TABLE userdb.employeetable;
-- Assumes a table named employeetable does not exists.
-- Throws exception
DROP TABLE employeetable;
Error: org.apache.spark.sql.AnalysisException: Table or view not found: employeetable;
(state=,code=0)
-- Assumes a table named employeetable does not exists,Try with IF EXISTS
-- this time it will not throw exception
DROP TABLE IF EXISTS employeetable;
{% endhighlight %}