SQL

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SQL

The program can retrieve data using two methods:

 

1. Table name. In this case, the program will read all columns from the specified table. The program will automatically build the SELECT SQL query.

2. SQL statement. You can specify your SQL statement with necessary columns. Also, you can query data from several tables. For example:

 

SELECT COL1, COL2 FROM DATA

 

sqlsrc2

Fig. 2.10.2 SQL

 

Select interval - the program will execute the selected query every specified interval.

 

Check new data by column - you can specify a column name that the program will use to select new data only. After each query, the program will store a maximum value, and next time will select new data only. If you do not specify a column name, then the program will read all data from a database with every query. It can be useful if your table contains just a few records that are being updated periodically.