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  1. Calcite
  2. CALCITE-2302

Implicit type cast support

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Details

    • Improvement
    • Status: Closed
    • Critical
    • Resolution: Fixed
    • 1.17.0
    • 1.21.0
    • core

    Description

      Now many DBs have support implicit type cast, eg: SqlServer, Oracle, Hive.

      Implicit type cast is an useful function for many cases, So we should support this.

      I checkout Calcite code and found that:

      1. Now we use a validator to validate our operands types[ through kinds of namespaces and scopes ]
      2. Most of the validations will finally goes to 
        SqlOperator.validateOperands
      1. which will use validation logic defined in corresponding SqlOperandTypeChecker

      What i'm confused about is where should i put the implicit type cast logic in? I figured out 2 ways:

      1. Supply a tool class/rules to add casts into a parsed SqlNode tree which will then go through the validation logic later on.
      2. Unleash the validation logic in kinds of SqlOperandTypeChecker, then modify the RelNode/RexNodes tree converted from a validated SqlNode tree to add in casts through custom RelOptRules.

      So guys, which of the 2 ways should i go, or if there are better way to do this?

      I need your help.

       

      Updated 18-05-30:

      Hi guys, i have made a PR in CALCITE-2302

      This is design doc: Calcite Implicit Type Cast Design.

      This is the type conversion matrix: Type Conversion Matrix.

      I really appreciate your suggestions, thx.

      Attachments

        Issue Links

          causes

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-3315 Multiple failures in Druid IT tests due to implicit casts

          • Blocker - Blocks development and/or testing work, production could not run
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-3360 SqlValidator throws NPE for unregistered function without implicit type coercion

          • Major - Major loss of function.
          • Closed
          contains

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-2829 Use consistent types when processing ranges

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. CALCITE-3217 Support "SELECT NULL"

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Closed
          is related to

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-2921 Allow NULL as argument to function calls

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-3326 SQL with invalid function throws NullPointerException if typeCoercion is disabled

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-2745 RexSimplify fails with ClassCastException when the expression contains comparisons of operands with different types

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-5156 Support implicit number type cast for IN Sub-query

          • Major - Major loss of function.
          • In Progress

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-2325 Calcite can not verify a explicit cast column in some scenario

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. CALCITE-3327 Simplify SqlValidatorTest by replacing 'boolean typeCoercion' parameter with fluent method 'Sql.withTypeCoercion(boolean)'

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. CALCITE-3423 Support using CAST operation and BOOLEAN type value in table macro

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. CALCITE-3206 Better error message when param type incompatibility

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. CALCITE-3331 Support implicit type cast for operators that use single operand family checker

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Closed
          links to

          Web Link Design of Calcite Implicit Type Cast

          Web Link GitHub Pull Request #706

          Web Link PR706

          Activity

            People

              danny0405 Danny Chen
              danny0405 Danny Chen
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