Documentation Home
MySQL 5.7 Reference Manual
Related Documentation Download this Manual
PDF (US Ltr) - 35.6Mb
PDF (A4) - 35.6Mb
PDF (RPM) - 34.7Mb
EPUB - 8.7Mb
HTML Download (TGZ) - 8.5Mb
HTML Download (Zip) - 8.5Mb
HTML Download (RPM) - 7.3Mb
Eclipse Doc Plugin (TGZ) - 9.4Mb
Eclipse Doc Plugin (Zip) - 11.5Mb
Man Pages (TGZ) - 203.5Kb
Man Pages (Zip) - 310.2Kb
Info (Gzip) - 3.3Mb
Info (Zip) - 3.3Mb
Excerpts from this Manual

14.2.3 DO Syntax

DO expr [, expr] ...

DO executes the expressions but does not return any results. In most respects, DO is shorthand for SELECT expr, ..., but has the advantage that it is slightly faster when you do not care about the result.

DO is useful primarily with functions that have side effects, such as RELEASE_LOCK().

Example: This SELECT statement pauses, but also produces a result set:

mysql> SELECT SLEEP(5);
+----------+
| SLEEP(5) |
+----------+
|        0 |
+----------+
1 row in set (5.02 sec)

DO, on the other hand, pauses without producing a result set.:

mysql> DO SLEEP(5);
Query OK, 0 rows affected (4.99 sec)

This could be useful, for example in a stored function or trigger, which prohibit statements that produce result sets.

DO only executes expressions. It cannot be used in all cases where SELECT can be used. For example, DO id FROM t1 is invalid because it references a table.

As of MySQL 5.7.8, DO statement errors that previously were converted to warnings are returned as errors.


User Comments
Sign Up Login You must be logged in to post a comment.