Use the LIMIT
clause to restrict the number of returned rows. When you use a single integer n with LIMIT
, the first n rows will be returned. Use the ORDER BY clause to control which rows come first. You can also select a number of rows after an offset using either of the following:
LIMIT offset, row_count
LIMIT row_count OFFSET offset
When you provide an offset m with a limit n, the first m rows will be ignored, and the following n rows will be returned.
Executing an UPDATE with the LIMIT
clause is not safe for replication. LIMIT 0
is an exception to this rule (see MDEV-6170 ).
There is a LIMIT ROWS EXAMINED optimization which provides the means to terminate the execution of SELECT statements which examine too many rows, and thus use too many resources. See LIMIT ROWS EXAMINED.
It is possible to use LIMIT
(or ORDER BY) in a multi-table UPDATE statement.
It is not possible to use LIMIT
(or ORDER BY) in a multi-table UPDATE statement.
CREATE TABLE members (name VARCHAR(20));
INSERT INTO members VALUES('Jagdish'),('Kenny'),('Rokurou'),('Immaculada');
SELECT * FROM members;
+------------+
| name |
+------------+
| Jagdish |
| Kenny |
| Rokurou |
| Immaculada |
+------------+
Select the first two names (no ordering specified):
SELECT * FROM members LIMIT 2;
+---------+
| name |
+---------+
| Jagdish |
| Kenny |
+---------+
All the names in alphabetical order:
SELECT * FROM members ORDER BY name;
+------------+
| name |
+------------+
| Immaculada |
| Jagdish |
| Kenny |
| Rokurou |
+------------+
The first two names, ordered alphabetically:
SELECT * FROM members ORDER BY name LIMIT 2;
+------------+
| name |
+------------+
| Immaculada |
| Jagdish |
+------------+
The third name, ordered alphabetically (the first name would be offset zero, so the third is offset two):
SELECT * FROM members ORDER BY name LIMIT 2,1;
+-------+
| name |
+-------+
| Kenny |
+-------+
From MariaDB 10.3.2, LIMIT
can be used in a multi-table update:
CREATE TABLE warehouse (product_id INT, qty INT);
INSERT INTO warehouse VALUES (1,100),(2,100),(3,100),(4,100);
CREATE TABLE store (product_id INT, qty INT);
INSERT INTO store VALUES (1,5),(2,5),(3,5),(4,5);
UPDATE warehouse,store SET warehouse.qty = warehouse.qty-2, store.qty = store.qty+2
WHERE (warehouse.product_id = store.product_id AND store.product_id >= 1)
ORDER BY store.product_id DESC LIMIT 2;
SELECT * FROM warehouse;
+------------+------+
| product_id | qty |
+------------+------+
| 1 | 100 |
| 2 | 100 |
| 3 | 98 |
| 4 | 98 |
+------------+------+
SELECT * FROM store;
+------------+------+
| product_id | qty |
+------------+------+
| 1 | 5 |
| 2 | 5 |
| 3 | 7 |
| 4 | 7 |
+------------+------+
When using LIMIT
with GROUP_CONCAT, you can simplify certain queries. Consider this table:
CREATE TABLE d (dd DATE, cc INT);
INSERT INTO d VALUES ('2017-01-01',1);
INSERT INTO d VALUES ('2017-01-02',2);
INSERT INTO d VALUES ('2017-01-04',3);
The following query works fine, but is rather complex:
SELECT SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(":",dd,cc)
ORDER BY cc DESC),",",1) FROM d;
+----------------------------------------------------------------------------+
| SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(":",dd,cc) ORDER BY cc DESC),",",1) |
+----------------------------------------------------------------------------+
| 2017-01-04:3 |
+----------------------------------------------------------------------------+
It can be simplified to this:
SELECT GROUP_CONCAT(CONCAT_WS(":",dd,cc)
ORDER BY cc DESC LIMIT 1) FROM d;
+-------------------------------------------------------------+
| GROUP_CONCAT(CONCAT_WS(":",dd,cc) ORDER BY cc DESC LIMIT 1) |
+-------------------------------------------------------------+
| 2017-01-04:3 |
+-------------------------------------------------------------+
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