Before you can create a query, you must know the information you want to retrieve from the database. For example, you might want to display all the Analog Input blocks with a current value greater than 50. Alternatively, you might want to display every block in alarm area Line5 for a specific I/O driver.
Once you know the information you want to display, you can construct the query using the following syntax:
{column} operator "value"
or
"value" operator {column}
where column is a column heading you want to display, enclosed in curved brackets, operator is one of the relational operators listed in the table Relational Operators, and value is a number or string enclosed with quotation marks (" ").
|
Operator |
Meaning |
|
= |
Equal to |
|
<= |
Less than or equal to |
|
< |
Less than |
|
!= |
Not equal to |
|
>= |
Greater than or equal to |
|
> |
Greater than |
Case Sensitivity
Strings entered in a query are not case sensitive. For example, a query such as:
{Tag Name} = "AI*"
retrieves blocks with names that start with AI. It also retrieves blocks with names that start with:
- Ai
- ai
- aI
When entering a number, the block's EGU range determines the maximum and minimum values you can enter. The following table lists these limits. To learn more about the EGU range, refer to the section Understanding EGU Limits.
Each query you create is evaluated from left to right.
