Extract tables from JOIN statements.

TODO

@@ -2,9 +2,9 @@
 * [o] Add JOIN to the list of keywords and provide proper autocompletion for it. 
 * [ ] Add a page to keep track of changelog in pgcli.com
 * [ ] Refactor to sqlcompletion to consume the text from left to right and use a state machine to suggest cols or tables instead of relying on hacks.
-* [ ] Extract tables should also look for table names after the JOIN keyword.
+* [X] Extract tables should also look for table names after the JOIN keyword.
         - SELECT * FROM some_very_long_table_name s JOIN another_fairly_long_name a ON s.id = a.num;
-* [ ] Test if the aliases are identified correctly if the AS keyword is used
+* [X] Test if the aliases are identified correctly if the AS keyword is used
         - SELECT * FROM my_table AS m WHERE m.a > 5;
 * [ ] ON keyword should suggest aliases. This is something we don't currently support since a collection of aliases is not maintained.
 * [ ] Add a page to keep track of changelog in pgcli.com

pgcli/packages/parseutils.py

@@ -74,19 +74,21 @@ def extract_from_part(parsed, stop_at_punctuation=True):
             if is_subselect(item):
                 for x in extract_from_part(item, stop_at_punctuation):
                     yield x
+            elif stop_at_punctuation and item.ttype is Punctuation:
+                raise StopIteration
             # An incomplete nested select won't be recognized correctly as a
             # sub-select. eg: 'SELECT * FROM (SELECT id FROM user'. This causes
             # the second FROM to trigger this elif condition resulting in a
             # StopIteration. So we need to ignore the keyword if the keyword
             # FROM.
-            elif stop_at_punctuation and item.ttype is Punctuation:
-                raise StopIteration
-            elif item.ttype is Keyword and item.value.upper() != 'FROM':
+            # Also 'SELECT * FROM abc JOIN def' will trigger this elif
+            # condition. So we need to ignore the keyword JOIN.
+            elif item.ttype is Keyword and item.value.upper() not in ('FROM', 'JOIN'):
                 raise StopIteration
             else:
                 yield item
         elif ((item.ttype is Keyword or item.ttype is Keyword.DML) and
-                item.value.upper() in ('FROM', 'INTO', 'UPDATE', 'TABLE', )):
+                item.value.upper() in ('FROM', 'INTO', 'UPDATE', 'TABLE', 'JOIN',)):
             tbl_prefix_seen = True
         # 'SELECT a, FROM abc' will detect FROM as part of the column list.
         # So this check here is necessary.
@@ -118,6 +120,13 @@ def extract_table_identifiers(token_stream):
 
 # extract_tables is inspired from examples in the sqlparse lib.
 def extract_tables(sql, include_alias=False):
+    """Extract the table names from an SQL statment.
+
+    Returns a list of table names if include_alias=False (default).
+    If include_alias=True, then a dictionary is returned where the keys are
+    aliases and values are real table names.
+
+    """
     parsed = sqlparse.parse(sql)
     if not parsed:
         return []

tests/test_parseutils.py

@@ -1,5 +1,10 @@
 from pgcli.packages.parseutils import extract_tables
 
+
+def test_empty_string():
+    tables = extract_tables('')
+    assert tables == []
+
 def test_simple_select_single_table():
     tables = extract_tables('select * from abc')
     assert tables == ['abc']
@@ -31,3 +36,14 @@ def test_simple_insert_single_table():
 def test_simple_update_table():
     tables = extract_tables('update abc set id = 1')
     assert tables == ['abc']
+
+def test_join_table():
+    tables = extract_tables('SELECT * FROM abc a JOIN def d ON s.id = a.num')
+    assert tables == ['abc', 'def']
+
+def test_join_as_table():
+    expected = {'m': 'my_table'}
+    assert extract_tables(
+            'SELECT * FROM my_table AS m WHERE m.a > 5') == expected.values()
+    assert extract_tables(
+            'SELECT * FROM my_table AS m WHERE m.a > 5', True) == expected