HEXISTS
Syntax
        HEXISTS key field
- Available since:
 - 2.0.0
 - Time complexity:
 - O(1)
 - ACL categories:
 - 
              
                
@read,@hash,@fast, 
Returns if field is an existing field in the hash stored at key.
Examples
RESP2/RESP3 Reply
One of the following:
- Integer reply: 
0if the hash does not contain the field, or the key does not exist. - Integer reply: 
1if the hash contains the field.