`
alamb opened a new issue, #2606:
URL: https://github.com/apache/arrow-datafusion/issues/2606
**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
DataFusion mostly follows postgres when it comes to compatibility. However, it also supports some usability features from mysql, notably `SHOW TABLES`;
It would be nice to also get basic schema information (column names, types) about a table using `DESCRIBE <TABLE>`
**Describe the solution you'd like**
I would like to run this sequence of commands and get a nicely formatted output other than an error:
```sql
❯ create table foo as select * from (values (1), (3), (2), (10), (8));
+---------+
| column1 |
+---------+
| 1 |
| 3 |
| 2 |
| 10 |
| 8 |
+---------+
5 rows in set. Query took 0.005 seconds.
❯ show tables;
+---------------+--------------------+------------+------------+
| table_catalog | table_schema | table_name | table_type |
+---------------+--------------------+------------+------------+
| datafusion | public | foo | BASE TABLE |
| datafusion | information_schema | tables | VIEW |
| datafusion | information_schema | columns | VIEW |
+---------------+--------------------+------------+------------+
3 rows in set. Query took 0.001 seconds.
❯ describe foo;
NotImplemented("Unsupported SQL statement: ExplainTable { describe_alias: true, table_name: ObjectName([Ident { value: \"foo\", quote_style: None }]) }")
```
Here is what mysql does (the table definition is different than the example above):
```sql
mysql> describe foo;
+-------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------+------+-----+---------+-------+
| bar | set('a','b') | YES | | NULL | |
| baz | enum('a','b') | YES | | NULL | |
+-------+---------------+------+-----+---------+-------+
2 rows in set (0.00 sec)
```
Note that the information *is* accesable via information_schema so this ticket would just plumbing it all together:
```sql
❯ select * from information_schema.columns;
+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+
| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |
+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+
| datafusion | public | foo | column1 | 0 | | YES | Int64 | | | | | | | |
+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+
1 row in set. Query took 0.004 seconds.
```
**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.
**Additional context**
Add any other context or screenshots about the feature request here.
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[GitHub] [arrow-datafusion] alamb closed issue #2606: Support `DESCRIBE
` to show table schemas
Posted by GitBox <gi...@apache.org>.
alamb closed issue #2606: Support `DESCRIBE <table>` to show table schemas
URL: https://github.com/apache/arrow-datafusion/issues/2606
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[GitHub] [arrow-datafusion] xudong963 commented on issue #2606: Support `DESCRIBE
` to show table schemas
Posted by GitBox <gi...@apache.org>.
xudong963 commented on issue #2606:
URL: https://github.com/apache/arrow-datafusion/issues/2606#issuecomment-1138138101
> Hi @alamb, can I work on this? I want to learn the implementation of datafusion by implementing this.
Feel free to pick it, fighting!
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[GitHub] [arrow-datafusion] LiuYuHui commented on issue #2606: Support `DESCRIBE
` to show table schemas
Posted by GitBox <gi...@apache.org>.
LiuYuHui commented on issue #2606:
URL: https://github.com/apache/arrow-datafusion/issues/2606#issuecomment-1138061517
Hi @alamb, can I work on this? I want to learn the implementation of datafusion by implementing this.
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