[SPARK-21653] Complement SQL expression document

• Type: Umbrella
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.0
• Component/s: SQL
• Assignee: Unassigned
• Reporter: L. C. Hsieh
• Created: 07/Aug/17 08:08
• Updated: 12/Dec/22 18:10
• Resolved: 21/Sep/17 13:51

Description

We have ExpressionDescription for SQL expressions. The expression description tells what an expression's usage, arguments, and examples. Users can understand how to use those expressions by DESCRIBE command in SQL:

spark-sql> DESCRIBE FUNCTION EXTENDED In;
Function: in
Class: org.apache.spark.sql.catalyst.expressions.In
Usage: expr1 in(expr2, expr3, ...) - Returns true if `expr` equals to any valN.
Extended Usage:
    No example/argument for in.

Not all SQL expressions have complete description now. For example, in the above case, there is no example for function in. This task is going to complement the expression description.

Sub-Tasks

• Complement predicates expression description: Resolved
• Add expression description for CASE WHEN: Resolved