Additional Features
Restricting the Number of Loops
The LOOPS= option restricts the number
of iterations of the inner loop in PROC SQL. By setting a limit, you
can prevent queries from consuming excessive resources.
For example, joining
three large tables without meeting the join-matching conditions could
create a huge internal table that would be inefficient to process.
Use the LOOPS= option to prevent this from happening.
You can
use the PROMPT | NOPROMPT option to modify the effect of the LOOPS=
option so that you are prompted to stop or continue processing when
the limit set by the LOOPS= option is reached.
Note: You
can use the number of iterations that are reported in the SQLOOPS
macro variable (after each PROC SQL statement is executed) to gauge
an appropriate value for the LOOPS= option. For more information about
the SQLOOPS macro variable, see the SAS documentation for the SQL
procedure.
Stopping Execution in PROC SQL after an Error
You already
know that you can use the EXEC | NOEXEC option to specify whether
a statement should be executed after its syntax is checked for accuracy.
If the EXEC option is in effect, SAS checks the PROC SQL syntax for
accuracy and, if no error is found, executes the SQL statement.
The ERRORSTOP | NOERRORSTOP option specifies whether
PROC SQL stops executing if it encounters an error. This option is
useful only when the EXEC option is in effect. The default is ERRORSTOP
in batch or in a noninteractive session and NOERRORSTOP in an interactive
SAS session.
ERRORSTOP instructs
PROC SQL to stop executing the statements but to continue checking
the syntax after it has encountered an error. ERRORSTOP has an effect
only when SAS is running in batch or in noninteractive execution mode.
NOERRORSTOP instructs
PROC SQL to execute the statements and to continue checking the syntax
after an error occurs. NOERRORSTOP is useful if you want a batch job
to continue executing SQL procedure statements after an error is encountered.
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