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  1. Tajo
  2. TAJO-408 Improve function system
  3. TAJO-482

Implements listing functions and describing a specified function.

    Details

    • Type: Sub-task
    • Status: Resolved
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.8.0
    • Component/s: Function/UDF
    • Labels:
      None

      Description

      I propose function related commands in Tajo's shell. This command is similar to PostgreSQL but a little different.

      • \df: list all functions
      • \df <function name>: list all functions which have a specified name(PostgreSQL uses a pattern matching).
      tajo> \df
                        List of functions
      Name | Result data type | Argument data types | Type 
      -----+------------------+---------------------+-------------
      avg  | FLOAT8           | INT8                | AGGREGATION
      sum  | INT8             | INT8                | AGGREGATION
      sum  | INT4             | INT4                | AGGREGATION
      sum  | FLOAT4           | FLOAT4              | AGGREGATION
      ...
      (80 rows)
      
      tajo> \df sum
                        List of functions
      Name | Result data type | Argument data types | Type 
      -----+------------------+---------------------+-------------
      sum  | INT8             | INT8                | AGGREGATION
      sum  | INT4             | INT4                | AGGREGATION
      sum  | FLOAT4           | FLOAT4              | AGGREGATION
      
      (3 rows)
      
      Function: INT8 sum(expr INT8)
      Description: The sum of a set of numbers.
      Example: 
      > select sum(*)
      

      When describing a specified function
      if all functions have same description, prints out first function description. Otherwise prints out all function.

      tajo> \df to_char
      
                        List of functions
        Name  |  Result data type | Argument data types | Type 
      --------+-------------------+---------------------+-------------
      to_char | TEXT              | TIMETSTAMP, TEXT    | GENERAL
      to_char | TEXT              | INT4                | GENERAL
      
      (2 rows)
      
      Function: TEXT to_char(timestamp TIMETSTAMP, pattern TEXT)
      Description: convert time stamp to string.
      Example: 
      > select to_char(current_timestamp, 'HH12:MI:SS');
      11:34:52
      
      Function: TEXT to_char(pattern INT4)
      Description: convert time stamp to string.
      Example: 
      > select to_char(25, '000');
      025
      

        Attachments

        1. TAJO-482.patch
          44 kB
          Hyoungjun Kim

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              • Assignee:
                hjkim Hyoungjun Kim
                Reporter:
                hjkim Hyoungjun Kim
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                Dates

                • Created:
                  Updated:
                  Resolved: