The ALTER SEQUENCE statement changes the name, increment values, and other settings of a sequence.
This statement performs a schema change. For more information about how online schema changes work in CockroachDB, see Online Schema Changes.
Required privileges
The user must have the CREATE privilege on the parent database.
Synopsis
Parameters
| Parameter | Description |
|---|---|
IF EXISTS |
Modify the sequence only if it exists; if it does not exist, do not return an error. |
sequence_name |
The name of the sequence you want to modify. |
INCREMENT |
The new value by which the sequence is incremented. A negative number creates a descending sequence. A positive number creates an ascending sequence. |
MINVALUE |
The new minimum value of the sequence. Default: 1 |
MAXVALUE |
The new maximum value of the sequence. Default: 9223372036854775807 |
START |
The value the sequence starts at if you RESTART or if the sequence hits the MAXVALUE and CYCLE is set. RESTART and CYCLE are not implemented yet. |
CYCLE |
The sequence will wrap around when the sequence value hits the maximum or minimum value. If NO CYCLE is set, the sequence will not wrap. |
Examples
Change the increment value of a sequence
In this example, we're going to change the increment value of a sequence from its current state (i.e., 1) to 2.
> ALTER SEQUENCE customer_seq INCREMENT 2;
Next, we'll add another record to the table and check that the new record adheres to the new sequence.
> INSERT INTO customer_list (customer, address) VALUES ('Marie', '333 Ocean Ave');
> SELECT * FROM customer_list;
+----+----------+--------------------+
| id | customer | address |
+----+----------+--------------------+
| 1 | Lauren | 123 Main Street |
| 2 | Jesse | 456 Broad Ave |
| 3 | Amruta | 9876 Green Parkway |
| 5 | Marie | 333 Ocean Ave |
+----+----------+--------------------+
Set the next value of a sequence
In this example, we're going to change the next value of the example sequence (customer_seq). Currently, the next value will be 7 (i.e., 5 + INCREMENT 2). We will change the next value to 20.
MAXVALUE or MINVALUE of the sequence. > SELECT setval('customer_seq', 20, false);
+--------+
| setval |
+--------+
| 20 |
+--------+
The setval('seq_name', value, is_called) function in CockroachDB SQL mimics the setval() function in PostgreSQL, but it does not store the is_called flag. Instead, it sets the value to val - increment for false or val for true.
Let's add another record to the table to check that the new record adheres to the new next value.
> INSERT INTO customer_list (customer, address) VALUES ('Lola', '333 Schermerhorn');
+----+----------+--------------------+
| id | customer | address |
+----+----------+--------------------+
| 1 | Lauren | 123 Main Street |
| 2 | Jesse | 456 Broad Ave |
| 3 | Amruta | 9876 Green Parkway |
| 5 | Marie | 333 Ocean Ave |
| 20 | Lola | 333 Schermerhorn |
+----+----------+--------------------+
See also
RENAME SEQUENCECREATE SEQUENCEDROP SEQUENCE- Functions and Operators
- Other SQL Statements
- Online Schema Changes
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