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Translate to NULLIF #31682

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roji opened this issue Sep 11, 2023 · 2 comments · May be fixed by #35327
Open

Translate to NULLIF #31682

roji opened this issue Sep 11, 2023 · 2 comments · May be fixed by #35327
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@roji
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area-query customer-reported type-enhancement
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10.0.0

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@roji
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roji commented Sep 11, 2023

All relational database support, NULLIF, which is the inverse of COALESCE: NULLIF(value, '(none)') returns null if value is (none), otherwise the value is returned

Database Functions
PostgreSQL NULLIF
MySQL NULLIF
MariaDB NULLIF
SQLite NULLIF
SQL Server NULLIF
Oracle NULLIF
@roji roji mentioned this issue Sep 11, 2023
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@bricelam
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Oh funny, I thought I already filed an issue for this. It turns out it was just a comment. #16092 (comment)

@ajcvickers ajcvickers added this to the Backlog milestone Sep 22, 2023
@cloudlucky cloudlucky mentioned this issue Jan 3, 2024
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@roji roji mentioned this issue Dec 12, 2024
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@roji roji self-assigned this Dec 13, 2024
@roji roji modified the milestones: Backlog, 10.0.0 Dec 13, 2024
roji added a commit to roji/efcore that referenced this issue Dec 13, 2024
@roji
Translate to NULLIF
70b2aa5 
Closes dotnet#31682
@roji roji linked a pull request Dec 13, 2024 that will close this issue
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roji added a commit to roji/efcore that referenced this issue Dec 13, 2024
@roji
Translate to NULLIF
438ecd9 
Closes dotnet#31682
roji added a commit to roji/efcore that referenced this issue Dec 13, 2024
@roji
Translate to NULLIF
d598bfb 
Closes dotnet#31682
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roji commented Dec 13, 2024

One nice effect of this lifting (a == b ? null : a -> NULLIF(a, b)) is that it eliminates duplicate expression evaluation (a), which, if the expression is complex/expensive (e.g. a subquery), could be quite impactful for perf.

roji added a commit to roji/efcore that referenced this issue Dec 18, 2024
@roji
Translate to NULLIF
03fd843 
Closes dotnet#31682
@roji roji removed the closed-fixed label Mar 17, 2025
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Translate to NULLIF roji/efcore
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