How to Use HGET in Redis: Syntax and Examples
Use the
HGET command in Redis to get the value of a specific field from a hash stored at a key. The syntax is HGET key field, which returns the value or null if the field does not exist.Syntax
The HGET command retrieves the value associated with a given field in a hash stored at a specified key.
- key: The name of the hash.
- field: The specific field within the hash whose value you want.
redis
HGET key field
Example
This example shows how to store a hash with user information and then retrieve the user's email using HGET.
redis
127.0.0.1:6379> HSET user:1000 name "Alice" email "alice@example.com" age "30" (integer) 3 127.0.0.1:6379> HGET user:1000 email "alice@example.com"
Output
"alice@example.com"
Common Pitfalls
Common mistakes when using HGET include:
- Trying to get a field from a key that does not exist returns
null. - Requesting a field that is not in the hash also returns
null. - Using
HGETon a key that is not a hash results in an error.
Always ensure the key exists and is a hash before using HGET.
redis
127.0.0.1:6379> HGET user:1000 phone (nil) 127.0.0.1:6379> SET notahash "value" OK 127.0.0.1:6379> HGET notahash field (error) WRONGTYPE Operation against a key holding the wrong kind of value
Output
(nil)
OK
(error) WRONGTYPE Operation against a key holding the wrong kind of value
Quick Reference
| Command | Description | Return Value |
|---|---|---|
| HGET key field | Get value of field in hash at key | Value or null if field/key missing |
| HSET key field value | Set field in hash at key | 1 if new field, 0 if updated |
| HEXISTS key field | Check if field exists in hash | 1 if exists, 0 if not |
Key Takeaways
HGET retrieves the value of a specific field from a hash stored at a key.
If the key or field does not exist, HGET returns null.
Using HGET on a non-hash key causes an error.
Always verify the key is a hash before using HGET to avoid errors.
HGET syntax is simple: HGET key field.