diff --git a/docs/en/12-taos-sql/06-select.md b/docs/en/12-taos-sql/06-select.md
index 786444ad77..1271e262ab 100644
--- a/docs/en/12-taos-sql/06-select.md
+++ b/docs/en/12-taos-sql/06-select.md
@@ -181,6 +181,14 @@ In TDengine, the first column of all tables must be a timestamp. This column is
 select _rowts, max(current) from meters;
 ```
 
+**\_IROWTS**
+
+The \_IROWTS pseudocolumns can only be used with INTERP FUNCTION. This pseudocolumns can be used to retrieve the corresponding timestamp column associated with the INTERPOLATION results.
+
+```sql
+select _irowts, interp(current) from meters range('2020-01-01 10:00:00', '2020-01-01 10:30:00') every(1s) fill(linear);
+```
+
 ## Query Objects
 
 `FROM` can be followed by a number of tables or super tables, or can be followed by a sub-query.
diff --git a/docs/en/12-taos-sql/20-keywords.md b/docs/en/12-taos-sql/20-keywords.md
index f7eb067c96..4b479b866b 100644
--- a/docs/en/12-taos-sql/20-keywords.md
+++ b/docs/en/12-taos-sql/20-keywords.md
@@ -343,6 +343,7 @@ The following list shows all reserved keywords:
 ### \_
 
 - \_C0
+- \_IROWTS
 - \_QDURATION
 - \_QEND
 - \_QSTART
diff --git a/docs/en/12-taos-sql/29-changes.md b/docs/en/12-taos-sql/29-changes.md
index 8532eeac5d..78b6d5fc05 100644
--- a/docs/en/12-taos-sql/29-changes.md
+++ b/docs/en/12-taos-sql/29-changes.md
@@ -11,12 +11,13 @@ description: "This document explains how TDengine SQL has changed in version 3.0
 | 1 | VARCHAR | Added | Alias of BINARY.
 | 2 | TIMESTAMP literal | Added | TIMESTAMP 'timestamp format' syntax now supported.
 | 3 | _ROWTS pseudocolumn | Added | Indicates the primary key. Alias of _C0.
-| 4 | INFORMATION_SCHEMA | Added |	Database for system metadata containing all schema definitions
-| 5 | PERFORMANCE_SCHEMA | Added | Database for system performance information.
-| 6 | Connection queries | Deprecated | Connection queries are no longer supported. The syntax and interfaces are deprecated.
-| 7 | Mixed operations | Enhanced | Mixing scalar and vector operations in queries has been enhanced and is supported in all SELECT clauses.
-| 8 | Tag operations | Added | Tag columns can be used in queries and clauses like data columns.
-| 9 | Timeline clauses and time functions in supertables | Enhanced | When PARTITION BY is not used, data in supertables is merged into a single timeline.
+| 4 | _IROWTS pseudocolumn | Added | Used to retrieve timestamps with INTERP function.
+| 5 | INFORMATION_SCHEMA | Added |	Database for system metadata containing all schema definitions
+| 6 | PERFORMANCE_SCHEMA | Added | Database for system performance information.
+| 7 | Connection queries | Deprecated | Connection queries are no longer supported. The syntax and interfaces are deprecated.
+| 8 | Mixed operations | Enhanced | Mixing scalar and vector operations in queries has been enhanced and is supported in all SELECT clauses.
+| 9 | Tag operations | Added | Tag columns can be used in queries and clauses like data columns.
+| 10 | Timeline clauses and time functions in supertables | Enhanced | When PARTITION BY is not used, data in supertables is merged into a single timeline.
 
 ## SQL Syntax