You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
Copy file name to clipboardExpand all lines: docs/en/06-advanced/01-subscription/01-topic.md
+5-5Lines changed: 5 additions & 5 deletions
Display the source diff
Display the rich diff
Original file line number
Diff line number
Diff line change
@@ -31,10 +31,10 @@ CREATE TOPIC [IF NOT EXISTS] topic_name as subquery;
31
31
This SQL query subscribes to data using a SELECT statement (for example, SELECT * or SELECT ts, c1), and may include filter conditions and scalar function calculations. However, aggregate functions and time-window aggregations are not supported.
32
32
33
33
1. Once this type of topic is created, the structure of the subscribed data is fixed.
34
-
2. Columns or tags that are subscribed to or referenced in calculations cannot be deleted (`ALTER TABLE DROP`) or modified (`ALTER TABLE MODIFY`). From 3.4.0.0, you can modify and delete, but you need to reload the topic.
35
-
3.If the table schema changes, any newly added columns will not appear in the subscription result.
36
-
4.For SELECT \*, the subscription expands to include all columns present at creation time. For subtables and normal tables, these are data columns; for supertables, they include both data and tag columns.
37
-
5.Query subscription on virtual tables is not supported.
34
+
2. Columns or tags that are subscribed to or referenced in calculations cannot be deleted (`ALTER TABLE DROP`) or modified (`ALTER TABLE MODIFY`). From 3.4.0.0, you can modify or delete or add, but you need to execute the command of "reload topic".
35
+
3.For SELECT \*, the subscription expands to include all columns present at creation time. For subtables and normal tables, these are data columns; for supertables, they include both data and tag columns.
36
+
4.Query subscription on virtual tables is not supported.
37
+
5.The super table, sub-table, and regular table within the subquery can be deleted. After deletion, the subscribed data becomes empty. If the table is recreated after deletion, the subscribed data remains empty because the table ID has changed. If you want to subscribe to the new table data, you can reload the topic using the reload topic syntax
38
38
39
39
For example, if you need to subscribe to all smart meter records where the voltage is greater than 200, and only return the timestamp, current, and voltage (excluding the phase), you can create a topic named `power_topic` with the following SQL statement:
40
40
@@ -97,7 +97,7 @@ SHOW TOPICS;
97
97
RELOAD TOPIC IF EXISTS topic_name as subquery;
98
98
```
99
99
100
-
1. This syntax is supported since version 3.3.9 and is used to reload topics. It primarily addresses issues where the output results do not take effect after deleting or adding columns and tags in queries involving topic changes or tag lengths, as well as when selecting * to query subscriptions.
100
+
1. This syntax is supported since version 3.4.0 and is used to reload topics. It primarily addresses issues where the output results do not take effect after deleting or adding columns and tags in queries involving topic changes or tag lengths, as well as when selecting * to query subscriptions.
101
101
2. When it is necessary to change the schema of the subscription table structure, first stop consuming, then make the change, execute "reload topic", and then restart the subscription.
102
102
103
103
The above SQL statement displays information about all topics in the current database.
Copy file name to clipboardExpand all lines: docs/en/14-reference/03-taos-sql/40-tmq.md
+3-3Lines changed: 3 additions & 3 deletions
Display the source diff
Display the rich diff
Original file line number
Diff line number
Diff line change
@@ -21,10 +21,10 @@ CREATE TOPIC [IF NOT EXISTS] topic_name as subquery
21
21
Subscribe through a `SELECT` statement (including `SELECT *`, or specific query subscriptions like `SELECT ts, c1`, which can include conditional filtering and scalar function calculations, but do not support aggregate functions or time window aggregation). It is important to note:
22
22
23
23
- Once this type of TOPIC is created, the structure of the subscribed data is fixed.
24
-
- Columns or tags that are subscribed to or used for calculations cannot be deleted (`ALTER table DROP`) or modified (`ALTER table MODIFY`). From 3.4.0.0, you can modify and delete, but you need to reload the topic.
25
-
- If there are changes to the table structure, new columns will not appear in the results.
24
+
- Columns or tags that are subscribed to or used for calculations cannot be deleted (`ALTER table DROP`) or modified (`ALTER table MODIFY`). From 3.4.0.0, you can modify or delete or add, but you need to execute the command of "reload topic".
26
25
- For `select *`, the subscription expands to include all columns at the time of creation (data columns for subtables and basic tables, data columns plus tag columns for supertables).
27
26
- Query subscription on virtual tables is not supported.
27
+
- The super table, sub-table, and regular table within the subquery can be deleted. After deletion, the subscribed data becomes empty. If the table is recreated after deletion, the subscribed data remains empty because the table ID has changed. If you want to subscribe to the new table data, you can reload the topic using the reload topic syntax
28
28
29
29
### Supertable topic
30
30
@@ -81,7 +81,7 @@ SHOW TOPICS;
81
81
RELOAD TOPIC IF EXISTS topic_name as subquery;
82
82
```
83
83
84
-
- This syntax is supported since version 3.3.9 and is used to reload topics. It primarily addresses issues where the output results do not take effect after deleting or adding columns and tags in queries involving topic changes or tag lengths, as well as when selecting * to query subscriptions.
84
+
- This syntax is supported since version 3.4.0 and is used to reload topics. It primarily addresses issues where the output results do not take effect after deleting or adding columns and tags in queries involving topic changes or tag lengths, as well as when selecting * to query subscriptions.
85
85
- When it is necessary to change the schema of the subscription table structure, first stop consuming, then make the change, execute "reload topic", and then restart the subscription.
86
86
87
87
Displays information about all topics in the current database.
Copy file name to clipboardExpand all lines: docs/en/14-reference/05-connector/40-csharp.md
+2Lines changed: 2 additions & 0 deletions
Display the source diff
Display the rich diff
Original file line number
Diff line number
Diff line change
@@ -72,11 +72,13 @@ For error code information please refer to [Error Codes](../09-error-code.md)
72
72
| JSON | byte[]|
73
73
| VARBINARY | byte[]|
74
74
| GEOMETRY | byte[]|
75
+
| BLOB | byte[]|
75
76
| DECIMAL | decimal |
76
77
77
78
**Note**:
78
79
79
80
- JSON type is only supported in tags.
81
+
- BLOB type is not supported as a tag column and does not support stmt parameterized query binding.
80
82
- The GEOMETRY type is binary data in little endian byte order, conforming to the WKB standard. For more details, please refer to [Data Types](../03-taos-sql/01-datatype.md)
81
83
For WKB standard, please refer to [Well-Known Binary (WKB)](https://libgeos.org/specifications/wkb/)
82
84
- The DECIMAL type in C# is represented using the `decimal` type, which supports high-precision decimal numbers.
0 commit comments