HP 3000 Manuals

ALLBASE/SQL Reference Manual

Chapter 9  Search Conditions 

This chapter discusses search condition clauses and the predicates used
in them.  The following sections are presented:

   *   Search Condition
   *   BETWEEN Predicate
   *   Comparison Predicate
   *   EXISTS Predicate
   *   IN Predicate
   *   LIKE Predicate
   *   NULL Predicate
   *   Quantified Predicate

A search condition specifies criteria for choosing rows to select,
update, delete, insert, permit in a table, or fire rules on.  Search
conditions are parameters in the following statements:

   *   In the SELECT statement, search conditions are used for two
       purposes as follows:

          *   In the WHERE clause, to determine rows to retrieve for
              further processing.  The only expressions not valid in this
              clause are aggregate functions and expressions containing
              LONG columns that are not in long column functions.

          *   In the HAVING clause, to specify a test to apply to each
              group of rows surviving the GROUP BY clause test(s).  If a
              GROUP BY clause is not used, the test is applied to all the
              rows meeting the WHERE clause conditions.  References in a
              HAVING clause to non-grouping columns must be from within
              aggregate functions.  Grouping columns can be referred to
              by name or with an aggregate function.

   *   In the UPDATE statement, search conditions in the WHERE clause
       identify rows that qualify for updating.

   *   In the DELETE statement, search conditions in the WHERE clause
       identify rows that qualify for deletion.

   *   In the INSERT statement, search conditions in the embedded SELECT
       statement identify rows to copy from one or more tables or views
       into a table.

   *   In the DECLARE CURSOR statement, search conditions in the embedded
       SELECT statement identify rows and columns to be processed with a
       cursor.

   *   In the CREATE VIEW statement, search conditions in the embedded
       SELECT statement identify rows and columns that qualify for the
       view.

   *   In table CHECK constraints, the search condition identifies valid
       rows that a table may contain.

   *   In rule firing conditions, search conditions identify conditions
       that will cause rules to fire.

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