Docs for --save and --dump plus made SQL optional for those, refs #273

docs/cli.rst

@@ -279,6 +279,35 @@ To read from standard input, use ``-`` as the filename - then use ``stdin`` or `
 
     $ cat example.csv | sqlite-utils memory - "select * from stdin"
 
+.. _cli_query_memory_dump_save:
+
+--dump and --save
+-----------------
+
+You can dump out the SQL used for the temporary in-memory database, complete with all imported data, using the ``--dump`` option::
+
+    % sqlite-utils memory dogs.csv --dump
+    BEGIN TRANSACTION;
+    CREATE TABLE [dogs] (
+        [rowid] TEXT,
+        [id] TEXT,
+        [dog_age] TEXT,
+        [name] TEXT
+    );
+    INSERT INTO "dogs" VALUES('1','1','4','Cleo');
+    INSERT INTO "dogs" VALUES('2','2','2','Pancakes');
+    INSERT INTO "dogs" VALUES('3','2','3','Pancakes');
+    CREATE VIEW t1 AS select * from [dogs];
+    CREATE VIEW t AS select * from [dogs];
+    COMMIT;
+
+Passing ``--save other.db`` will instead use that SQL to populate a new database file::
+
+    % sqlite-utils memory dogs.csv --save dogs.db
+
+These features are mainly intented as debugging tools - for much more finely grained control over how data is inserted into a SQLite database file see :ref:`cli_inserting_data` and :ref:`cli_insert_csv_tsv`.
+
+
 .. _cli_rows:
 
 Returning all rows in a table

sqlite_utils/cli.py

@@ -1143,6 +1143,10 @@ def memory(
 ):
     "Execute SQL query against an in-memory database, optionally populated by imported data"
     db = sqlite_utils.Database(memory=True)
+    # If --dump or --save used but no paths detected, assume SQL query is a path:
+    if (dump or save) and not paths:
+        paths = [sql]
+        sql = None
     for i, path in enumerate(paths):
         if path == "-":
             csv_fp = sys.stdin

tests/test_cli_memory.py

@@ -34,10 +34,11 @@ def test_memory_csv(tmpdir, sql_from, use_stdin):
     )
 
 
-def test_memory_dump():
+@pytest.mark.parametrize("extra_args", ([], ["select 1"]))
+def test_memory_dump(extra_args):
     result = CliRunner().invoke(
         cli.cli,
-        ["memory", "-", "select 1", "--dump"],
+        ["memory", "-"] + extra_args + ["--dump"],
         input="id,name\n1,Cleo\n2,Bants",
     )
     assert result.exit_code == 0
@@ -55,11 +56,12 @@ def test_memory_dump():
     )
 
 
-def test_memory_save(tmpdir):
+@pytest.mark.parametrize("extra_args", ([], ["select 1"]))
+def test_memory_save(tmpdir, extra_args):
     save_to = str(tmpdir / "save.db")
     result = CliRunner().invoke(
         cli.cli,
-        ["memory", "-", "select 1", "--save", save_to],
+        ["memory", "-"] + extra_args + ["--save", save_to],
         input="id,name\n1,Cleo\n2,Bants",
     )
     assert result.exit_code == 0