1. In the second example above, different formats are used in the two rows to be inserted. In the first row, the timestamp format is a date and time string, which is interpreted from the string value only. In the second row, the timestamp format is a long integer, which will be interpreted based on the database time precision.
2. When trying to insert multiple rows in single statement, only the timestamp of one row can be set as NOW, otherwise there will be duplicate timestamps among the rows and the result may be out of expectation because NOW will be interpreted as the time when the statement is executed.
2. When trying to insert multiple rows in a single statement, only the timestamp of one row can be set as NOW, otherwise there will be duplicate timestamps among the rows and the result may be out of expectation because NOW will be interpreted as the time when the statement is executed.
3. The oldest timestamp that is allowed is subtracting the KEEP parameter from current time.
4. The newest timestamp that is allowed is adding the DAYS parameter to current time.
If no columns are explicitly specified, all the columns must be provided with values, this is called "all column mode". The insert performance of all column mode is much better than specifying a part of columns, so it's encouraged to use "all column mode" while providing NULL value explicitly for the columns for which no actual value can be provided.
If no columns are explicitly specified, all the columns must be provided with values, this is called "all column mode". The insert performance of all column mode is much better than specifying a subset of columns, so it's encouraged to use "all column mode" while providing NULL value explicitly for the columns for which no actual value can be provided.
:::
## Insert Into Multiple Tables
One or multiple rows can be inserted into multiple tables in single SQL statement, with or without specifying specific columns.
One or multiple rows can be inserted into multiple tables in a single SQL statement, with or without specifying specific columns.
If it's not sure whether the table already exists, the table can be created automatically while inserting using below SQL statement. To use this functionality, a STable must be used as template and tag values must be provided.
If it's unknown whether the table already exists, the table can be created automatically while inserting using the SQL statement below. To use this functionality, a STable must be used as template and tag values must be provided.
@@ -87,19 +87,19 @@ INSERT INTO d21001 USING meters TAGS ('California.SanFrancisco', 2) VALUES ('202
```
:::info
Prior to version 2.0.20.5, when using `INSERT` to create table automatically and specify the columns, the column names must follow the table name immediately. From version 2.0.20.5, the column names can follow the table name immediately, also can be put between `TAGS` and `VALUES`. In same SQL statement, however, these two ways of specifying column names can't be mixed.
Prior to version 2.0.20.5, when using `INSERT` to create tables automatically and specifying the columns, the column names must follow the table name immediately. From version 2.0.20.5, the column names can follow the table name immediately, also can be put between `TAGS` and `VALUES`. In the same SQL statement, however, these two ways of specifying column names can't be mixed.
:::
## Insert Rows From A File
Besides using `VALUES` to insert one or multiple rows, the data to be inserted can also be prepared in a CSV file with comma as separator and each field value quoted by single quotes. Table definition is not required in the CSV file. For example, if file "/tmp/csvfile.csv" contains below data:
Besides using `VALUES` to insert one or multiple rows, the data to be inserted can also be prepared in a CSV file with comma as separator and each field value quoted by single quotes. Table definition is not required in the CSV file. For example, if file "/tmp/csvfile.csv" contains the below data:
```
'2021-07-13 14:07:34.630', '10.2', '219', '0.32'
'2021-07-13 14:07:35.779', '10.15', '217', '0.33'
```
Then data in this file can be inserted by below SQL statement:
Then data in this file can be inserted by the SQL statement below:
```sql
INSERTINTOd1001FILE'/tmp/csvfile.csv';
...
...
@@ -107,13 +107,13 @@ INSERT INTO d1001 FILE '/tmp/csvfile.csv';
## Create Tables Automatically and Insert Rows From File
From version 2.1.5.0, tables can be automatically created using a super table as template when inserting data from a CSV file, Like below:
From version 2.1.5.0, tables can be automatically created using a super table as template when inserting data from a CSV file, like below:
@@ -122,15 +122,15 @@ INSERT INTO d21001 USING meters TAGS ('California.SanFrancisco', 2) FILE '/tmp/c
## More About Insert
For SQL statement like `insert`, stream parsing strategy is applied. That means before an error is found and the execution is aborted, the part prior to the error point has already been executed. Below is an experiment to help understand the behavior.
For SQL statement like `insert`, a stream parsing strategy is applied. That means before an error is found and the execution is aborted, the part prior to the error point has already been executed. Below is an experiment to help understand the behavior.
