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add _irowts in EN doc

This commit is contained in:
Ganlin Zhao 2022-09-28 17:28:23 +08:00
parent d7d2dabfe8
commit 8d510fcf18
3 changed files with 16 additions and 6 deletions
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8
docs/en/12-taos-sql/06-select.md
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@ -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.

1
docs/en/12-taos-sql/20-keywords.md
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@ -343,6 +343,7 @@ The following list shows all reserved keywords:
### \_
- \_C0
- \_IROWTS
- \_QDURATION
- \_QEND
- \_QSTART

13
docs/en/12-taos-sql/29-changes.md
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@ -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