fix(schema-compiler): Preserve full time buckets in period-over-perio…

[nchristo1213]

fix(schema-compiler): Preserve Full Time Buckets in Period-over-Period Queries

This PR replaces INNER JOIN with LEFT JOIN when stitching sub-queries in outerMeasuresJoinFullKeyQueryAggregate, ensuring all expected time buckets appear when calculating period-over-period (PoP) metrics.

Problem

When PoP queries used INNER JOIN, buckets missing from auxiliary sub-queries (q_1, q_2, ...) were dropped causing incomplete results or incorrect ratios.

Solution

Use LEFT JOIN instead, preserving all keys from the anchor query (q_0). Missing values in auxiliary queries yield NULL rather than removing the row entirely.

LEFT JOIN ${this.wrapInParenthesis((q))} as q_${i + 1} ON ${this.dimensionsJoinCondition(`q_${i}`, `q_${i + 1}`)}

Benefits

• Retains continuity for PoP metrics
• Allows ratio calculations to appear accurate when prior period data is missing
• Ensures accuracy without introducing gaps or dropped time buckets

Tests

• New fixture: sales cube with date, category, region, and PoP measures
• Adjusted:
  • CAGR: Added NULL rows
  • multi-stage graph tests: Added secondary ordering
• New tests:
  • Time-only PoP
  • One-dimension PoP
  • Two-dimension PoP

These tests ensure the correct number of periods appear and that PoP measures return NULL instead of dropping rows when previous-period values are unavailable.

Check List

• Tests have been run in packages where changes made if available
• Linter has been run for changed code
• Tests for the changes have been added if not covered yet
• Docs have been added / updated if required

resolves #9353

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.07%. Comparing base (32f9b79) to head (ab02440).
Report is 7 commits behind head on master.

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Flag	BASE (32f9b79)	HEAD (ab02440)
cubesql	1	0

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #9502       +/-   ##
===========================================
- Coverage   80.54%   59.07%   -21.48%     
===========================================
  Files         382      153      -229     
  Lines       96586    13017    -83569     
  Branches     2202     2202               
===========================================
- Hits        77797     7690    -70107     
+ Misses      18476     5014    -13462     
  Partials      313      313               

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