In Redis, the SADD command allows us to add members to a key. We can add multiple members if required.

A Redis set is an unordered collection of unique strings (members).

Syntax

The syntax goes like this:

SADD key member [member ...]

This allows us to add one or more members to the specified key.

Example

Here’s an example to demonstrate:

SADD animals "Cat" "Dog" "Ant"

Result:

(integer) 3

In this case, the set didn’t already exist and so I created the set and added three members to it.

We can take a look at the set like this:

SMEMBERS animals

Result:

1) "Ant"
2) "Dog"
3) "Cat"

We can see that the members have been added to the list as specified.

Let’s add another member:

SADD animals "Horse"

Result:

(integer) 1

Let’s check the set again:

SMEMBERS animals

Result:

1) "Horse"
2) "Ant"
3) "Dog"
4) "Cat"

We can see that the latest member has been added as specified.

Duplicate Values

If we try to add a value that already exists, the value isn’t added. This is because a Redis set consists of unique strings.

Let’s try to add the same value again:

SADD animals "Horse"

Result:

(integer) 0

Let’s check the set again:

SMEMBERS animals

Result:

1) "Horse"
2) "Ant"
3) "Dog"
4) "Cat"

We can see that the new value wasn’t added, because it already existed in the set.