[SPARK-29941] Support dec as shorthand for decimal

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.0.0
• Component/s: SQL
• Assignee: Kent Yao 2
• Reporter: Kent Yao 2
• Created: 18/Nov/19 10:07
• Updated: 29/Dec/19 05:25
• Resolved: 18/Nov/19 15:37

Description

CHAR is equivalent to CHARACTER. DEC is equivalent to DECIMAL. INT is equivalent to INTEGER. VARCHAR is equivalent to CHARACTER VARYING. ...

According to SQL standard, we decide to add dec for decimal as short hand.

also checked with Postgres,

```sql
postgres=# select dec '1.0';
numeric
---------
1.0
(1 row)

```

Issue Links

• links to: GitHub Pull Request #26574