b5ecc41c73
### What changes were proposed in this pull request? This PR is to clean up the markdown file in SHOW COLUMNS page. - remove the unneeded embedded inline HTML markup by using the basic markdown syntax. - use the ``` sql for highlighting the SQL syntax. ### Why are the changes needed? Make the doc cleaner and easily editable by MD editors. ### Does this PR introduce _any_ user-facing change? NO ### How was this patch tested? **Before**  **After**  Closes #28414 from gatorsmile/cleanupShowColumns. Lead-authored-by: Xiao Li <gatorsmile@gmail.com> Co-authored-by: gatorsmile <gatorsmile@gmail.com> Signed-off-by: gatorsmile <gatorsmile@gmail.com>
98 lines
2.5 KiB
Markdown
98 lines
2.5 KiB
Markdown
---
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layout: global
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title: SHOW COLUMNS
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displayTitle: SHOW COLUMNS
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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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Return the list of columns in a table. If the table does not exist, an exception is thrown.
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### Syntax
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```sql
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SHOW COLUMNS table_identifier [ database ]
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```
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### Parameters
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* **table_identifier**
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Specifies the table name of an existing table. The table may be optionally qualified
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with a database name.
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**Syntax:** `{ IN | FROM } [ database_name . ] table_name`
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**Note:** Keywords `IN` and `FROM` are interchangeable.
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* **database**
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Specifies an optional database name. The table is resolved from this database when it
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is specified. When this parameter is specified then table
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name should not be qualified with a different database name.
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**Syntax:** `{ IN | FROM } database_name`
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**Note:** Keywords `IN` and `FROM` are interchangeable.
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### Examples
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```sql
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-- Create `customer` table in `salesdb` database;
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USE salesdb;
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CREATE TABLE customer(
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cust_cd INT,
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name VARCHAR(100),
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cust_addr STRING);
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-- List the columns of `customer` table in current database.
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SHOW COLUMNS IN customer;
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+---------+
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| col_name|
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+---------+
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| cust_cd|
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| name|
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|cust_addr|
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+---------+
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-- List the columns of `customer` table in `salesdb` database.
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SHOW COLUMNS IN salesdb.customer;
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+---------+
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| col_name|
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+---------+
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| cust_cd|
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| name|
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|cust_addr|
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+---------+
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-- List the columns of `customer` table in `salesdb` database
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SHOW COLUMNS IN customer IN salesdb;
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+---------+
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| col_name|
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+---------+
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| cust_cd|
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| name|
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|cust_addr|
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+---------+
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```
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### Related Statements
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* [DESCRIBE TABLE](sql-ref-syntax-aux-describe-table.html)
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* [SHOW TABLE](sql-ref-syntax-aux-show-table.html)
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