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