feat: add compatible union and unit test

[tobegit3hub]

• Resolve https://github.com/4paradigm/OpenMLDB/issues/2477 .

[codecov[bot]]

Codecov Report

Base: 75.61% // Head: 75.61% // Increases project coverage by +0.00% :tada:

Coverage data is based on head (169aef1) compared to base (2720a67). Patch coverage: 50.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #2478   +/-   ##
=========================================
  Coverage     75.61%   75.61%           
  Complexity      386      386           
=========================================
  Files           644      644           
  Lines        121235   121234    -1     
  Branches       1056     1053    -3     
=========================================
+ Hits          91669    91671    +2     
+ Misses        29331    29328    -3     
  Partials        235      235           

Impacted Files	Coverage Δ
...om/_4paradigm/openmldb/batch/utils/SparkUtil.scala	75.38% <ø> (ø)
...digm/openmldb/batch/window/WindowAggPlanUtil.scala	61.94% <50.00%> (+0.54%)	:arrow_up:
src/sdk/db_sdk.cc	67.26% <0.00%> (-2.70%)	:arrow_down:
src/replica/replicate_node.cc	74.30% <0.00%> (-0.56%)	:arrow_down:
hybridse/src/codec/fe_row_codec.cc	78.26% <0.00%> (-0.16%)	:arrow_down:
src/storage/mem_table.cc	90.16% <0.00%> (-0.15%)	:arrow_down:
src/tablet/tablet_impl.cc	62.51% <0.00%> (-0.08%)	:arrow_down:
src/nameserver/name_server_impl.cc	43.69% <0.00%> (+0.12%)	:arrow_up:
src/zk/dist_lock.cc	83.33% <0.00%> (+1.51%)	:arrow_up:
... and 4 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

:umbrella: View full report at Codecov.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.

[github-actions[bot]]

SDK Test Report

  83 files    83 suites   1m 25s :stopwatch: 172 tests 165 :heavy_check_mark: 7 :zzz: 0 :x: 217 runs  210 :heavy_check_mark: 7 :zzz: 0 :x:

Results for commit 169aef14.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Linux Test Report

565 tests   558 :heavy_check_mark:  26m 8s :stopwatch:   57 suites      7 :zzz:   51 files        0 :x:

Results for commit 169aef14.

:recycle: This comment has been updated with latest results.

[tobegit3hub]

The added UT may be enable after this issue resolved https://github.com/4paradigm/OpenMLDB/issues/2639 .