diff --git a/cobol_testgen/__init__.py b/cobol_testgen/__init__.py
index 6362913..0b43ec6 100644
--- a/cobol_testgen/__init__.py
+++ b/cobol_testgen/__init__.py
@@ -958,9 +958,12 @@ def generate_data(cobol_source: str, structure: dict = None,
 
     if copybook_dirs:
         src_resolved = resolve_copybooks(cobol_source, '.', extra_search_paths=copybook_dirs)
+        src_resolved = resolve_sql_includes(src_resolved, '.')
         preprocessed = preprocess(src_resolved)
     else:
-        preprocessed = preprocess(cobol_source)
+        # Also try SQL include resolution without copybook
+        src_sql = resolve_sql_includes(cobol_source, '.')
+        preprocessed = preprocess(src_sql)
     data_div = extract_data_division(preprocessed)
     data_fields = parse_data_division(data_div) if data_div else []
 
@@ -1004,17 +1007,29 @@ def generate_data(cobol_source: str, structure: dict = None,
         ufn = fn.upper()
         if ' OF ' in ufn:
             fn = fn.split(' OF ')[0].strip()
+        if fn in _fdict_names:
+            return fn
+        # Check subscript: WS-PLAN-CODE(WS-PLAN-IDX) -> WS-PLAN-CODE
         m = re.match(r'^(\w[\w-]*)\s*\(', fn)
-        if m and m.group(1) in _fdict_names:
-            return m.group(1)
+        if m:
+            base = m.group(1)
+            if base in _fdict_names:
+                return base
+            # Check if any field in fdict starts with base + "("
+            if any(f.startswith(base + "(") for f in _fdict_names):
+                return base
         return fn
+    def _is_arith_expr(fn):
+        return any(op in fn for op in [' + ', ' - ', ' * ', ' / '])
+
     filtered_paths = []
     for cons_list, asgn, term in path_infos:
         clean = []
         for c in cons_list:
             if len(c) >= 4:
                 fn = _resolve_field(str(c[0]))
-                if fn in _fdict_names or fn.startswith("_"):
+                if fn in _fdict_names or fn.startswith("_") or _is_arith_expr(str(c[0])) or \
+                   any(f.startswith(fn + "(") for f in _fdict_names):
                     c = list(c); c[0] = fn
                     clean.append(tuple(c))
             else:
diff --git a/cobol_testgen/cond.py b/cobol_testgen/cond.py
index 1b7ea87..dd6a83e 100644
--- a/cobol_testgen/cond.py
+++ b/cobol_testgen/cond.py
@@ -94,20 +94,21 @@ def parse_single_condition(text, fields=None):
         text = text.split(' OF ')[0].strip()
 
     # COBOL class condition: WS-KEY-DGT-N NUMERIC
-    if re.match(r'^[A-Z][A-Z0-9-]*(?:\([^)]*\))?\s+(NUMERIC|ALPHABETIC|ALPHABETIC-UPPER|POSITIVE|NEGATIVE|ZERO)\s*$', text, re.IGNORECASE):
-        m = re.match(r'^([A-Z][A-Z0-9-]*(?:\([^)]*\))?)\s+(NUMERIC|ALPHABETIC|ALPHABETIC-UPPER|POSITIVE|NEGATIVE|ZERO)\s*$', text, re.IGNORECASE)
+    if re.match(r'^[A-Z][A-Z0-9_-]*(?:\([^)]*\))?\s+(NUMERIC|ALPHABETIC|ALPHABETIC-UPPER|POSITIVE|NEGATIVE|ZERO)\s*$', text, re.IGNORECASE):
+        m = re.match(r'^([A-Z][A-Z0-9_-]*(?:\([^)]*\))?)\s+(NUMERIC|ALPHABETIC|ALPHABETIC-UPPER|POSITIVE|NEGATIVE|ZERO)\s*$', text, re.IGNORECASE)
         return (m.group(1), '=', m.group(2).upper())
 
     # Bare field reference (no operator, no NOT): WS-EOF → WS-EOF = 'Y'
-    if re.match(r'^[A-Z][A-Z0-9-]*(?:\([^)]*\))?\s*$', text, re.IGNORECASE):
+    if re.match(r'^[A-Z][A-Z0-9_-]*(?:\([^)]*\))?\s*$', text, re.IGNORECASE):
         return (text, '=', 'Y')
 
     # Bare NOT field reference (no operator): NOT WS-EOF → WS-EOF <> 'Y'
     if text.upper().startswith('NOT ') and not re.search(r'(>=|<=|<>|>|<|=)', text):
         fn = text[4:].strip()
-        if re.match(r'^[A-Z][A-Z0-9-]*(?:\([^)]*\))?$', fn, re.IGNORECASE):
+        if re.match(r'^[A-Z][A-Z0-9_-]*(?:\([^)]*\))?$', fn, re.IGNORECASE):
             return (fn, '<>', 'Y')
 
+
     # NOT at start of condition: NOT WS-X > 50 → WS-X <= 50
     # Strip leading NOT, parse the inner condition, invert the operator
     if text.upper().startswith('NOT '):
@@ -135,14 +136,18 @@ def parse_single_condition(text, fields=None):
             normalized = re.sub(pat, repl, text, flags=re.IGNORECASE)
             break
 
-    # Standard regex: FIELD OP VALUE
-    m = re.match(
-        r"^(\w[\w-]*(?:\s*\([^)]*\))?)\s*(>=|<=|<>|>|<|=)\s*(.*)$",
-        normalized
-    )
-    if m:
-        field = re.sub(r'\s*([(),])\s*', r'\1', m.group(1))
-        return (field, m.group(2), m.group(3).strip().strip("'").strip('"'))
+    # FUNCTION call as left value: FUNCTION MOD(X, 2) NOT = 0 → _FUNC_MOD <> 0
+    if text.upper().startswith('FUNCTION '):
+        # After not_map normalization, NOT = has been converted to <>
+        func_match = re.match(
+            r'^FUNCTION\s+(\w+)\(([^)]*)\)\s*(>=|<=|<>|>|<|=)\s*(.*)$',
+            normalized, re.IGNORECASE
+        )
+        if func_match:
+            func_name = func_match.group(1).upper()
+            op = func_match.group(3)
+            val = func_match.group(4).strip().strip("'").strip('"')
+            return ('_FUNC_' + func_name, op, val)
 
     # Arithmetic expression regex (lazy match allows spaces in field expr)
     m = re.match(
@@ -156,8 +161,21 @@ def parse_single_condition(text, fields=None):
             field = field[:-4].strip()
         return (field, m.group(2), m.group(3).strip().strip("'").strip('"'))
 
-    # Bare field: WS-EOF (no operator) → treat as WS-EOF = 'Y'
-    if re.match(r'^[A-Z][A-Z0-9-]*(?:\([^)]*\))?$', text, re.IGNORECASE):
+    # Standard regex: FIELD OP VALUE
+    m = re.match(
+        r"^(\w[\w-]*(?:\s*\([^)]*\))?)\s*(>=|<=|<>|>|<|=)\s*(.*)$",
+        normalized
+    )
+    if m:
+        field = re.sub(r'\s*([(),])\s*', r'\1', m.group(1))
+        # Strip subscript/substring for matching: CDR-ID(1:3) -> CDR-ID
+        bare_m = re.match(r'^\w[\w-]*', field)
+        if bare_m:
+            field = bare_m.group(0)
+        return (field, m.group(2), m.group(3).strip().strip("'").strip('"'))
+
+    # Bare field: WS-EOF (no operator) -> WS-EOF = 'Y'
+    if re.match(r'^[A-Z][A-Z0-9_-]*(?:\([^)]*\))?\s*$', text, re.IGNORECASE):
         return (text, '=', 'Y')
 
     return None