# Make schema updates
<a name="make-schema-updates"></a>

This topic describes some of the changes that you can make to the schema in `CREATE TABLE` statements without actually altering your data. To update a schema, you can in some cases use an `ALTER TABLE` command, but in other cases you do not actually modify an existing table. Instead, you create a table with a new name that modifies the schema that you used in your original `CREATE TABLE` statement.

Depending on how you expect your schemas to evolve, to continue using Athena queries, choose a compatible data format. 

Consider an application that reads orders information from an `orders` table that exists in two formats: CSV and Parquet. 

The following example creates a table in Parquet:

```
CREATE EXTERNAL TABLE orders_parquet (
   `orderkey` int, 
   `orderstatus` string, 
   `totalprice` double, 
   `orderdate` string, 
   `orderpriority` string, 
   `clerk` string, 
   `shippriority` int
) STORED AS PARQUET
LOCATION 's3://amzn-s3-demo-bucket/orders_ parquet/';
```

The following example creates the same table in CSV:

```
CREATE EXTERNAL TABLE orders_csv (
   `orderkey` int, 
   `orderstatus` string, 
   `totalprice` double, 
   `orderdate` string, 
   `orderpriority` string, 
   `clerk` string, 
   `shippriority` int
) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
LOCATION 's3://amzn-s3-demo-bucket/orders_csv/';
```

The following topics show how updates to these tables affect Athena queries.

**Topics**
+ [Add columns at the beginning or in the middle of the table](updates-add-columns-beginning-middle-of-table.md)
+ [Add columns at the end of the table](updates-add-columns-end-of-table.md)
+ [Remove columns](updates-removing-columns.md)
+ [Rename columns](updates-renaming-columns.md)
+ [Reorder columns](updates-reordering-columns.md)
+ [Change a column data type](updates-changing-column-type.md)