php - how to make a varchar nullable and unique together in mysql (laravel) -

Can I make a MySQL column blank and unique? I have a table that stores email_id to users if the user wants to give it to others, it will be empty (blank). I have read in some other questions that I can create unique fields by default, but when I create a table, I receive this error

  # 1067 - Invalid default value for 'email' (I Only for test purpose)   
 The main table is generated with the Larva schema builder class  
  $ table-> Text ('email') - & gt; Faucet () - & gt; Unique (); (No default is added)   
 In DB  
  + -------------- + ----- - ------------ + ------ + ----- + --------- + ------------- - - + | Field | Type | Faucet Key | Default | Extra | + -------------- + ------------------ + ------ + ----- + - - ------ + ---------------- + | Email_id | Varchar (200) | Yes. United Nations Faucet |   
 key 'users_email_id_unique' (while entering an email with an empty string)    
  duplicate entry 
 question now This is how a varchar field is controlled, which is unique and tap together.   
 
 
 I know this is an old question, it is for those who have the same problem is.  
 You are trying to add a  empty  string, you have created the column  faucet  and  unique . This means that you are trying something that you should not do you can send multiple  blank  values, but multiple  empty  can not be string  
  
  Public function set emaill property ($ value) {if (if empty) on mysql  empty  value  
 Consider. ($ Value) {// empty string $ this- & gt; Features ['company'] = NULL; } And {$ this- & gt; Attributes ['company'] = $ value; }}