"(Cond1 OR Cond2) AND (Cond1)" equal to "Cond1"

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
30/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp, sql
Domain
database

Research direction

Start by reproducing the reported EF Core LINQ query and inspecting its generated SQL, focusing on the null-semantics predicate around DATEADD. Confirm whether the redundant condition can be simplified without changing results, then add regression coverage for the generated query and verify the SQL output.

Written by the indexing model from the issue text.

Description

area-query customer-reported

Hello,

EFCore: master (with some modifications).
Data provider: my own.

EFCore expression:

var recs=db.testTable.Where(r => r.DATA.AddYears(r.COL_INTEGER)==r.DATA.AddYears(1) && r.TEST_ID==testID);

Translated SQL:

SELECT "t"."TEST_ID", "t"."COL_INTEGER", "t"."COL_TIMESTAMP"
FROM "TEST_MODIFY_ROW" AS "t"
WHERE ((DATEADD(YEAR,"t"."COL_INTEGER","t"."COL_TIMESTAMP") = DATEADD(YEAR,1,"t"."COL_TIMESTAMP")) OR (("t"."COL_TIMESTAMP" IS NULL OR "t"."COL_INTEGER" IS NULL) AND "t"."COL_TIMESTAMP" IS NULL)) AND ("t"."TEST_ID" = :__testID_0)

If i right, you may replace

(("t"."COL_TIMESTAMP" IS NULL OR "t"."COL_INTEGER" IS NULL) AND "t"."COL_TIMESTAMP" IS NULL)
on the simple expression

"t"."COL_TIMESTAMP" IS NULL

:)

Dominant language
C#
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