diff --git a/docs/en/12-taos-sql/06-select.md b/docs/en/12-taos-sql/06-select.md
index ea0d7abc16b18a92147642d86b167d96903ebfda..b28d5acb1828ddb67cf1fc2615973409362063af 100644
--- a/docs/en/12-taos-sql/06-select.md
+++ b/docs/en/12-taos-sql/06-select.md
@@ -55,7 +55,7 @@ window_clause: {
   | INTERVAL(interval_val [, interval_offset]) [SLIDING (sliding_val)] [WATERMARK(watermark_val)] [FILL(fill_mod_and_val)]
 
 interp_clause:
-    RANGE(ts_val, ts_val) EVERY(every_val) FILL(fill_mod_and_val)
+    RANGE(ts_val [, ts_val]) EVERY(every_val) FILL(fill_mod_and_val)
 
 partition_by_clause:
     PARTITION BY expr [, expr] ...
diff --git a/docs/en/12-taos-sql/10-function.md b/docs/en/12-taos-sql/10-function.md
index b469da8f558014d9d4711b6348a84c90dd413c95..b517bcb3ccdd90b52d778914ba77db3dba71d393 100644
--- a/docs/en/12-taos-sql/10-function.md
+++ b/docs/en/12-taos-sql/10-function.md
@@ -889,9 +889,10 @@ ignore_null_values: {
 - `INTERP` is used to get the value that matches the specified time slice from a column. If no such value exists an interpolation value will be returned based on `FILL` parameter.
 - The input data of `INTERP` is the value of the specified column and a `where` clause can be used to filter the original data. If no `where` condition is specified then all original data is the input.
 - `INTERP` must be used along with `RANGE`, `EVERY`, `FILL` keywords.
-- The output time range of `INTERP` is specified by `RANGE(timestamp1,timestamp2)` parameter, with timestamp1 <= timestamp2. timestamp1 is the starting point of the output time range and must be specified. timestamp2 is the ending point of the output time range and must be specified.
+- The output time range of `INTERP` is specified by `RANGE(timestamp1,timestamp2)` parameter, with timestamp1 <= timestamp2. timestamp1 is the starting point of the output time range. timestamp2 is the ending point of the output time range.
 - The number of rows in the result set of `INTERP` is determined by the parameter `EVERY(time_unit)`. Starting from timestamp1, one interpolation is performed for every time interval specified `time_unit` parameter. The parameter `time_unit` must be an integer, with no quotes, with a time unit of: a(millisecond)), s(second), m(minute), h(hour), d(day), or w(week). For example, `EVERY(500a)` will interpolate every 500 milliseconds.
 - Interpolation is performed based on `FILL` parameter. For more information about FILL clause, see [FILL Clause](../distinguished/#fill-clause).
+- When only one timestamp value is specified in `RANGE` clause, `INTERP` is used to generate interpolation at this point in time. In this case, `EVERY` clause can be omitted. For example, SELECT INTERP(col) FROM tb RANGE('2023-01-01 00:00:00') FILL(linear).
 - `INTERP` can be applied to supertable by interpolating primary key sorted data of all its childtables. It can also be used with `partition by tbname` when applied to supertable to generate interpolation on each single timeline.
 - Pseudocolumn `_irowts` can be used along with `INTERP` to return the timestamps associated with interpolation points(support after version 3.0.2.0).
 - Pseudocolumn `_isfilled` can be used along with `INTERP` to indicate whether the results are original records or data points generated by interpolation algorithm(support after version 3.0.3.0).
@@ -902,7 +903,7 @@ ignore_null_values: {
 - We want to downsample every 1 hour and use a linear fill for missing values. Note the order in which the "partition by" clause and the "range", "every" and "fill" parameters are used.
 
 ```sql
-SELECT _irowts,INTERP(current) FROM test.meters PARTITION BY TBNAME RANGE('2017-07-22 00:00:00','2017-07-24 12:25:00') EVERY(1h) FILL(LINEAR) 
+SELECT _irowts,INTERP(current) FROM test.meters PARTITION BY TBNAME RANGE('2017-07-22 00:00:00','2017-07-24 12:25:00') EVERY(1h) FILL(LINEAR)
 ```
 
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