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https://issues.apache.org/jira/browse/CALCITE-3959?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17709063#comment-17709063
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Joey Moore edited comment on CALCITE-3959 at 4/5/23 8:12 PM:
-------------------------------------------------------------
I've started work on this issue and have a few questions about the best way to
implement. The
[INSTR|https://cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#instr]
function seems to be a superset of the functionality of
[STRPOS|https://cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#strpos]
and the standard SQL
[Position|https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/sql/fun/SqlPositionFunction.java]
function that is implemented in calcite. It can perform the same tasks as
those as well as do backwards search with a negative position operand, and has
an occurrence operand that doesn't appear in any of the other functions.
Because of this there seem to be many ways to implement it,
* desugar into position when occurrence = 1 and position > 0
* desugar Position and STRPOS into INSTR as it's the most general
** Is desugaring into a dialect specific function a bad idea?
* implement it separately of the other functions
I'm still quite new to the codebase, so I'm not sure the overreaching effects
of any of these. [~julianhyde] please let me know what you think would be best,
or if I've missed a more elegant solution
was (Author: JIRAUSER299634):
I've started work on this issue and have a few questions about the best way to
implement. The
[INSTR|https://cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#instr]
function seems to be a superset of the functionality of
[STRPOS|https://cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#strpos]
and the standard SQL
[Position|https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/sql/fun/SqlPositionFunction.java]
function that is implemented in calcite. It can perform the same tasks as
those as well as do backwards search with a negative position operand, and has
an occurrence operand that doesn't appear in any of the other functions.
Because of this there seem to be many ways to implement it,
* desugar into position when occurrence = 1 and position > 0
* desugar Position and STRPOS into INSTR as it's the most general
* implement it separately of the other functions
I'm still quite new to the codebase, so I'm not sure the overreaching effects
of any of these. [~julianhyde] please let me know what you think would be best,
or if I've missed a more elegant solution
> Implement INSTR function
> ------------------------
>
> Key: CALCITE-3959
> URL: https://issues.apache.org/jira/browse/CALCITE-3959
> Project: Calcite
> Issue Type: Wish
> Reporter: xzh_dz
> Assignee: Joey Moore
> Priority: Major
>
> Implement INSTR function
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