WHERE Clause Considerations

A WHERE clause is used to specify criteria for selection of one or more occurrences of a logical record that is the object of an ERASE, MODIFY, OBTAIN, or STORE command. A WHERE clause is also used to direct LRF to a particular logical record path.
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A WHERE clause is used to specify criteria for selection of one or more occurrences of a logical record that is the object of an ERASE, MODIFY, OBTAIN, or STORE command. A WHERE clause is also used to direct LRF to a particular logical record path.
Considerations
  • A WHERE clause is specified in the form of an expression that consists of one or more conditions to be tested.
    • Multiple conditions are combined with the logical operators AND and OR.
    • The logical operator NOT can precede a single condition or a compound condition that is enclosed in parentheses. NOT specifies the opposite of the condition.
  • A test condition is expressed as a comparison or a keyword.
  • A logical record occurrence is selected only if the entire expression evaluates as true.
  • Operators in a conditional expression are evaluated one at a time, from left to right, in order of precedence.
    Note:
    The default order of precedence is the same as that described for other conditional expressions discussed in Conditional Expressions.