Add round, ceil, floor, truncate to the In-Database Column type

distribution/lib/Standard/Table/0.0.0-dev/src/Data/Column.enso

@@ -707,6 +707,16 @@ type Column
          If `decimal_places` is outside the range -15..15 (inclusive), an
          `Illegal_Argument` error is thrown.
 
+       ! Precision
+         As floating-point numbers are inexact, rounding can have unexpected
+         results near the precision limit (about 15 decimal places), especially
+         when rounding mid-point values. For example:
+
+         Postgres: rounding 1.2222222222222235 to 15 decimal places returns:
+             1.222222222222224
+         SQLite: rounding 1.2222222222222235 to 15 decimal places returns:
+             1.222222222222223
+
        ? Negative decimal place counts
          Rounding to `n` digits can be thought of as "rounding to the nearest
          multiple of 10^(-n)". For negative decimal counts, this results in

test/Table_Tests/src/Database/Postgres_Spec.enso

@@ -194,7 +194,7 @@ postgres_specific_spec connection db_name setup =
             Test.with_clue "d.value_type="+d.value_type.to_display_text+": " <|
                 d.value_type.variable_length.should_be_true
 
-    Test.group "[PostgreSQL] math functions" <|
+    Test.group "[PostgreSQL] math functionsasdfasdf" <|
         Test.specify "round, trunc, ceil, floor" <|
             col = table_builder [["x", [0.1, 0.9, 3.1, 3.9, -0.1, -0.9, -3.1, -3.9]]] . at "x"
             col . cast Value_Type.Integer . ceil . value_type . should_equal Value_Type.Float
@@ -229,6 +229,18 @@ postgres_specific_spec connection db_name setup =
             result.to_vector.at 0
         do_round n dp=0 use_bankers=False = do_op n (_.round dp use_bankers)
 
+        Test.specify "Can round correctly near the precision limit" <|
+            do_round 1.2222222222222225 15 . should_equal 1.222222222222223
+            do_round -1.2222222222222225 15 . should_equal -1.222222222222223
+            do_round 1.2222222222222235 15 . should_equal 1.222222222222224
+            do_round -1.2222222222222235 15 . should_equal -1.222222222222224
+
+        Test.specify "Can round correctly near the precision limit, using banker's rounding" <|
+            do_round 1.2222222222222225 15 use_bankers=True . should_equal 1.222222222222222
+            do_round -1.2222222222222225 15 use_bankers=True . should_equal -1.222222222222222
+            do_round 1.2222222222222235 15 use_bankers=True . should_equal 1.222222222222224
+            do_round -1.2222222222222235 15 use_bankers=True . should_equal -1.222222222222224
+
         Test.specify "Can handle NaN/Infinity" <|
             nan_result = if setup.test_selection.is_nan_and_nothing_distinct then Number.nan else Nothing
             ops = [.round, .truncate, .ceil, .floor]

test/Table_Tests/src/Database/SQLite_Spec.enso

@@ -123,7 +123,7 @@ sqlite_specific_spec prefix connection setup =
             expected_code = code_template.replace "{Tinfo}" tinfo
             t.distinct ["strs"] . to_sql . prepare . should_equal [expected_code, []]
 
-    Test.group "[PostgreSQL] math functions" <|
+    Test.group "[PostgreSQL] math functionsasdfasdf" <|
         Test.specify "round, trunc, ceil, floor" <|
             col = table_builder [["x", [0.1, 0.9, 3.1, 3.9, -0.1, -0.9, -3.1, -3.9]]] . at "x"
 
@@ -157,6 +157,18 @@ sqlite_specific_spec prefix connection setup =
             result.to_vector.at 0
         do_round n dp=0 use_bankers=False = do_op n (_.round dp use_bankers)
 
+        Test.specify "Can round correctly near the precision limit" <|
+            do_round 1.2222222222222225 15 . should_equal 1.222222222222223
+            do_round -1.2222222222222225 15 . should_equal -1.222222222222223
+            do_round 1.2222222222222235 15 . should_equal 1.222222222222223
+            do_round -1.2222222222222235 15 . should_equal -1.222222222222223
+
+        Test.specify "Can round correctly near the precision limit, using banker's rounding" <|
+            do_round 1.2222222222222225 15 use_bankers=True . should_equal 1.222222222222222
+            do_round -1.2222222222222225 15 use_bankers=True . should_equal -1.222222222222222
+            do_round 1.2222222222222235 15 use_bankers=True . should_equal 1.222222222222224
+            do_round -1.2222222222222235 15 use_bankers=True . should_equal -1.222222222222224
+
         Test.specify "Can handle NaN/Infinity" <|
             nan_result = if setup.test_selection.is_nan_and_nothing_distinct then Number.nan else Nothing
             ops = [.round, .truncate, .ceil, .floor]