7.6. Writing the Body Code - 7.6.12. FOR EXECUTE STATEMENT - 《Firebird 2.5 Language Reference》

7.6.12. FOR EXECUTE STATEMENT

7.6.12. `FOR EXECUTE STATEMENT`

Used for

Executing dynamically created SQL statements that return a row set

Available in

PSQL

Syntax

FOR <execute_statement> DO <compound_statement>

Table 89. `FOR EXECUTE STATEMENT` Statement Parameters
Argument	Description
execute_stmt	An `EXECUTE STATEMENT` statement
single_statement	A single statement, terminated with a colon, that performs all the processing for this `FOR` loop
compound_statement	A block of statements wrapped in `BEGIN…END`, that performs all the processing for this `FOR` loop

The statement FOR EXECUTE STATEMENT is used, in a manner analogous to FOR SELECT, to loop through the result set of a dynamically executed query that returns multiple rows.

Example

Executing a dynamically constructed SELECT query that returns a data set:

CREATE PROCEDURE DynamicSampleThree (
   Q_FIELD_NAME VARCHAR(100),
   Q_TABLE_NAME VARCHAR(100)
) RETURNS(
  LINE VARCHAR(32000)
)
AS
  DECLARE VARIABLE P_ONE_LINE VARCHAR(100);
BEGIN
  LINE = '';
  FOR
    EXECUTE STATEMENT
      'SELECT T1.' || :Q_FIELD_NAME ||
      ' FROM ' || :Q_TABLE_NAME || ' T1 '
    INTO :P_ONE_LINE
  DO
    IF (:P_ONE_LINE IS NOT NULL) THEN
      LINE = :LINE || :P_ONE_LINE || ' ';
  SUSPEND;
END