In Redis, the HSETNX command enables us to set a field in a hash, but only if the field doesn’t already exist. It sets the field at the specified key to the value we provide.
If the key doesn’t exist, it’s created with the specified hash value. If the field already exists, nothing is set (i.e. the command has no effect).
In Redis, the HSET command enables us to set one or more fields in a hash. It sets the field/s at the specified key to the value/s we provide.
If the key doesn’t exist, it’s created with the specified hash value. If the field already exists, it is overwritten with the new value.
In Redis, the SUNIONSTORE command does the same thing that SUNION does, except that it stores the result in a key. More specifically, it takes the members of the set resulting from the union of all of the given sets, and stores them in the specified key.
In Redis, the SUNION command returns the members of the set resulting from the union of all of the given sets.
In Redis, the SREM command allows us to remove one or more members from a set.
In Redis, the SPOP command removes and returns one or more random members from the set value store at the specified key.
This command is similar to the SRANDMEMBER command in that it returns one or more random members from a set, but SPOP removes it, whereas SRANDMEMBER doesn’t.
In Redis, the SMOVE command moves a member of a set from one key to another. In other words, the member is removed from the source set and added to the destination set.
In Redis, the SMEMBERS command returns all members of a given set. We specify the key name of the set when we call the command.
In Redis, we can use the SMISMEMBER command to find out whether one or more members are in a given set. It’s similar to the SISMEMBER command, except that it allows us to check more than one member at a time.
The SMISMEMBER command was introduced in Redis 6.2.0.