Step 5. Write an Expression

There are three basic questions you can ask the Query engine.

1 What are the values of all the attributes for an item in the same order you asked for them?
2 Does an item meet the expression criteria?
3 What items of a specified type match the expression?
Option 4.1. Open the Expression Browser through the Expression EditorOption 4.2. Open the TADB Attribute BrowserStep 7. Apply the Expression or Cancel the SessionStep 6. Test the Expression

Operators include:

Comparison Operators
For TADB attributes
= Logical EQUALS operator.
< Logical LESS THAN operator.
> Logical GREATER THAN operator.
<= Logical LESS THAN or EQUALS operator.
>= Logical GREATER THAN or EQUALS operator.
=l Logical SQL LIKE operator. Note: The appropriate information about acceptable wild cards and pattern matching characters can be found in SQL Server Books Online:
  1. Access the index.
  2. Select the entry called LIKE comparisons.
  3. Select the entry called LIKE Transact-SQL Reference.
=r Logical regular expression comparison operator.
For non-TADB attributes
= Logical EQUALS operator.
=r Logical regular expression comparison operator.
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Boolean Operators
! Logical NOT operator (placed before an expression)
& Logical AND operator.
| Logical OR operator
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Other Syntax Tools
( ) To group expression elements.
' ' To identify literal values
, To form sub-string expressions.
. To identify attributes
$$ To identify references to named expressions.
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Note: There is no Not Comparison Operator. When an expression should be a not expression, a ! is placed before the expression.