SADD command in redis

SADD key member

Add the specified member to the set value stored at the key. If a member is already a member of the set no operation is performed

Note

1. If the key does not exist a new set with the specified member as a sole member is created.

2. If the key exists but does not hold a set value an error is returned.

TIME COMPLEXITY: O(1)

RETURN VALUE: Integer reply, specifically:

1 if the new element was added

0 if the element was already a member of the set

Syntax:

SADD key member

Example 1: When key is not present or if present then held set.

redis:6379> SADD setKey 1000
(integer) 1

Output

1

Example 2: When the key is present and not held set.

redis:6379> SADD mykey 1000
(error) WRONGTYPE Operation against a key
           holding the wrong kind of value

Output

(error) WRONGTYPE Operation against a key holding the wrong kind of value