Summary

This PR fixes critical parsing issues in the SQLite engine where comparison operators were incorrectly defaulting to= and ORDER BY clauses were generating incorrect AST nodes. It also restores correct handling ofEXISTS/NOT EXISTS so SQLite queries emit the right boolean expressions and generated code.

Issues Fixed

1. Comparison operators not parsed correctly - All comparison expressions were defaulting to= operator instead of extracting the actual operator (<,>,<=,>=,!=,<>,IS,LIKE,GLOB,MATCH,REGEXP)
2. NOT operator variants not supported -NOT LIKE,NOT GLOB,NOT IN,IS NOT NULL, etc. were not handled properly
3. ORDER BY generates wrong AST nodes - ORDER BY clauses were incorrectly creatingCaseExpr nodes instead of properSortBy nodes
4. Missing ORDER BY integration - SELECT statements weren't properly setting theSortClause field
5. NOT EXISTS flattened incorrectly - SQLite treatedNOT EXISTS as a bare subquery, producingexists variables instead of the expectednot_exists boolean output

Changes Made

Core Fixes (internal/engine/sqlite/convert.go)

• EnhancedconvertComparison: Now properly extracts actual comparison operators instead of defaulting to=
• AddedextractComparisonOperator: Comprehensive function handling all SQLite comparison operators including NOT variants
• FixedconvertOrderby_stmtContext: Now generates properSortBy AST nodes with correct direction (ASC/DESC) and null handling (NULLS FIRST/LAST)
• EnhancedconvertMultiSelect_stmtContext: Added ORDER BY integration to properly setSortClause
• AddedconvertNullComparison: HandleIS NULL/IS NOT NULL expressions
• ExtendedconvertUnaryExpr: Detects unaryNOT via the unary-operator node, including wrappingNOT EXISTS as aBoolExpr
• HardenedconvertInSelectNode: RecognisesNOT EXISTS when the context begins with the NOT token so the AST preserves the negation

New Test Coverage (internal/engine/sqlite/convert_test.go)

• 35 comprehensive test cases covering all fixed functionality
• Comparison operator tests: All SQLite operators (<,>,<=,>=,=,!=,<>,<<,>>,&,|,IS,LIKE,GLOB,MATCH,REGEXP)
• NOT variant tests:NOT LIKE,NOT GLOB,NOT IN,IS NOT NULL, etc.
• ORDER BY tests: Direction handling, null ordering, multiple columns
• Complex query tests: Real-world scenarios with multiple operators and clauses

Operators Now Supported

• Comparison:<,>,<=,>=,=,!=,<>
• Bitwise:<<,>>,&,|
• Pattern matching:LIKE,GLOB,MATCH,REGEXP
• Null testing:IS NULL,IS NOT NULL
• List membership:IN,NOT IN
• All NOT variants:NOT LIKE,NOT GLOB,NOT MATCH,NOT REGEXP

Testing

# All new tests passgotest -v ./internal/engine/sqlite -run TestConvert# Existing functionality preservedgotest ./internal/engine/sqlite# Regression coverage for managed DB fixturesgotest ./internal/endtoend -run'TestReplay/managed-db/select_exists/sqlite'gotest ./internal/endtoend -run'TestReplay/managed-db/select_not_exists/sqlite'

Example Impact

Before (incorrect):

SELECT*FROM usersWHERE age>=18ORDER BY nameDESC-- Generated AST: A_Expr with "=" operator, CaseExpr for ordering

After (correct):

SELECT*FROM usersWHERE age>=18ORDER BY nameDESC-- Generated AST: A_Expr with ">=" operator, SortBy with DESC direction

Breaking Changes

• SQLiteEXISTS/NOT EXISTS return types: Generated Go methods now returnbool (and emit variables namedexists/not_exists) instead of the previousint64 placeholder. Projects that already consume these helpers must update their call sites to expect a boolean result.
• Parameter propagation forNOT EXISTS: Because the AST now retains the inner select, generated methods once again surface the query arguments. Call sites that relied on the buggy zero-argument signature will need to pass the correct inputs (for example,id inBarNotExists).

Related Issues

Fixes parsing issues with SQLite comparison operators and ORDER BY clauses that could lead to incorrect SQL generation and runtime errors.