get_query_table_aliases(query) is far from being final

.github/workflows/python-ci.yml

@@ -52,11 +52,11 @@ jobs:
         poetry run python --version
         poetry show
 
-    - name: Lint with pylint
-      run: poetry run pylint sql_metadata.py
-
     - name: Test with pytest
       run: poetry run pytest -vv --cov=sql_metadata --cov-report=term
 
+    - name: Lint with pylint
+      run: poetry run pylint sql_metadata.py
+
     - name: Build a distribution package
       run: poetry build -vvv

pyproject.toml

@@ -19,7 +19,7 @@ sqlparse = "^0.4.1"
 [tool.poetry.dev-dependencies]
 black = "^20.8b1"
 coverage = "^5.4"
-pylint = "^2.6.2"
+pylint = "^2.7.0"
 pytest = "^6.2.2"
 pytest-cov = "^2.11.1"
 

sql_metadata.py

@@ -366,26 +366,46 @@ def get_query_table_aliases(query: str) -> Dict[str, str]:
     will give you {'a': 'users1', 'b': 'users2'}
     """
     aliases = dict()
-    last_keyword_token = None
     last_table_name = None
+    token_list = get_query_tokens(query)
+    for prev_token, token, nxt_token in zip(
+        ["start"] + token_list, token_list, token_list[1:] + ["end"]
+    ):
 
-    for token in get_query_tokens(query):
-        # print(token.ttype, token, last_table_name)
-
-        # handle "FROM foo alias" syntax (i.e, "AS" keyword is missing)
-        # if last_table_name and token.ttype is Name:
-        #     aliases[token.value] = last_table_name
-        #     last_table_name = False
-
-        if last_keyword_token:
-            if last_keyword_token.value.upper() in ["FROM", "JOIN", "INNER JOIN"]:
+        if prev_token != "start":
+            if (
+                prev_token.value.upper() in ["FROM", "JOIN", "INNER JOIN", "LEFT JOIN"]
+                and token.value != "("
+            ):
                 last_table_name = token.value
-
-            elif last_table_name and last_keyword_token.value.upper() in ["AS"]:
-                aliases[token.value] = last_table_name
-                last_table_name = False
-
-        last_keyword_token = token if token.is_keyword else False
+            elif last_table_name:
+                if token.value == ".":
+                    last_table_name = last_table_name + token.value  # add the dot '.'
+                if (
+                    token.value == ","
+                    or token.is_keyword
+                    and token.value.upper() != "AS"
+                ):  # there is no alias
+                    aliases[""] = last_table_name
+                    last_table_name = False
+                if (
+                    prev_token.value.upper() == "AS"
+                ):  # if previous keyword was AS then we found the alias
+                    aliases[token.value] = last_table_name
+                    last_table_name = False
+                elif token.ttype is Name:
+                    if prev_token.value == ".":
+                        last_table_name = (
+                            last_table_name + token.value
+                        )  # add Name to last_table_name
+                    else:  # found alias
+                        aliases[token.value] = last_table_name
+                        last_table_name = False
+
+        if (
+            nxt_token == "end" and last_table_name
+        ):  # if the last token is a tablename then there is no alias
+            aliases[""] = last_table_name
 
     return aliases