what is lexical parameter?

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what is lexical parameter?..

Answer / rajeshwar

with this u can specify a complete where condition for
example select * from emp where &lex_par; i.e we can
specify where conditions.with bind variables we give values
to columns in query .

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what is lexical parameter?..

Answer / samaresh

Lexical references are placeholders for columns or
parameters that you embed in a SELECT statement. You can
use lexical references to replace the clauses appearing
after SELECT, FROM, WHERE, GROUP BY, ORDER BY, HAVING,
CONNECT BY, and START WITH. Use a lexical reference when
you want to substitute multiple values at runtime. You
cannot make lexical references in a PL/SQL statement. You
can, however, use a bind reference in PL/SQL to set the
value of a parameter that is then referenced lexically in
SQL, as shown in te example below. You create a lexical
reference by typing an ampersand (&) followed immediately
by the column or parameter name. A default definition is
not provided for lexical references.
Therefore, you must do the following:
Before you create your query, define a column or parameter
in the data model for each lexical reference in the query.
For columns, you must set the Value if Null property, and,
for parameters, you must set the Initial Value property.

Restrictions::::
You cannot make lexical references in a PL/SQL statement.

If a column or parameter is used as a lexical reference in
a query, its data type must be character.

If you want to use lexical references in your SELECT
clause, you should create a separate lexical reference for
each column you will substitute. In addition, you should
assign an alias to each lexical reference. This enables you
to use the same layout field and boilerplate label for
whatever value you enter for the lexical reference on the
Runtime Parameter Form.

If you use lexical references in your SELECT clause, you
must specify the same number of items at runtime as were
specified in the report's data model. Each value you
specify for your lexical references at runtime must have
the same datatype as its Initial Value.

A lexical reference cannot be used to create additional
bind variables after the After Form trigger fires. For
example, suppose you have a query like the following (note
that the WHERE clause is replaced by a lexical reference):
SELECT ENAME, SAL FROM EMP
&where_clauseIf the value of the where_clause parameter
contains a reference to a bind variable, you must specify
the value in the After Form trigger or earlier. You would
get an error if you supplied the following value for the
parameter in the Before Report trigger: WHERE SAL
= :new_bindIf you supplied this same value in the After
Form trigger, the report would run

Reports Builder uses these values to validate a query with
a lexical reference. Create your query containing lexical
references.