Double type argument for to_timestamp function

datafusion/expr/src/built_in_function.rs

@@ -959,6 +959,7 @@ impl BuiltinScalarFunction {
                 1,
                 vec![
                     Int64,
+                    Float64,
                     Timestamp(Nanosecond, None),
                     Timestamp(Microsecond, None),
                     Timestamp(Millisecond, None),

datafusion/physical-expr/src/datetime_expressions.rs

@@ -969,6 +969,24 @@ pub fn to_timestamp_invoke(args: &[ColumnarValue]) -> Result<ColumnarValue> {
         DataType::Int64 => {
             cast_column(&args[0], &DataType::Timestamp(TimeUnit::Second, None), None)
         }
+        DataType::Float64 => {
+            if let ColumnarValue::Scalar(ScalarValue::Float64(Some(float_ts))) = &args[0]
+            {
+                cast_column(
+                    &ColumnarValue::Scalar(ScalarValue::Int64(Some(
+                        (float_ts * 1_000_000_000_f64).trunc() as i64,
+                    ))),
+                    &DataType::Timestamp(TimeUnit::Nanosecond, None),
+                    None,
+                )
+            } else {
+                cast_column(
+                    &args[0],
+                    &DataType::Timestamp(TimeUnit::Nanosecond, None),
+                    None,
+                )
+            }
+        }
         DataType::Timestamp(_, None) => cast_column(
             &args[0],
             &DataType::Timestamp(TimeUnit::Nanosecond, None),

datafusion/sqllogictest/test_files/timestamps.slt

@@ -291,6 +291,35 @@ SELECT COUNT(*) FROM ts_data_secs where ts > to_timestamp_seconds('2020-09-08T12
 ----
 2
 
+
+# to_timestamp float inputs
+
+query P
+SELECT to_timestamp(1.1);
+----
+1970-01-01T00:00:01.100
+
+query P
+SELECT to_timestamp(-1.1);
+----
+1969-12-31T23:59:58.900
+
+query P
+SELECT to_timestamp(0.0);
+----
+1970-01-01T00:00:00
+
+query P
+SELECT to_timestamp(1.23456789);
+----
+1970-01-01T00:00:01.234567890
+
+query P
+SELECT to_timestamp(123456789.123456789);
+----
+1973-11-29T21:33:09.123456784
+
+
 # from_unixtime
 
 # 1599566400 is '2020-09-08T12:00:00+00:00'

docs/source/user-guide/sql/scalar_functions.md

@@ -1392,9 +1392,9 @@ extract(field FROM source)
 ### `to_timestamp`
 
 Converts a value to a timestamp (`YYYY-MM-DDT00:00:00Z`).
-Supports strings, integer, and unsigned integer types as input.
+Supports strings, integer, unsigned integer, and double types as input.
 Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00')
-Integers and unsigned integers are interpreted as seconds since the unix epoch (`1970-01-01T00:00:00Z`)
+Integers, unsigned integers, and doubles are interpreted as seconds since the unix epoch (`1970-01-01T00:00:00Z`)
 return the corresponding timestamp.
 
 ```