How to prevent duplicate entries but allow duplicates in one column MYSQL?-CodePudding

I have a MYSQL table that stores restaurant IDs to email address. Any given email address can have as many restaurant IDs added to it. for example:

| email VARCHAR(45) | restaurant-id VARCHAR(45) |

I currently have no primary key set because both columns need to be able to have duplicate entires. What I am looking to prevent is the following duplicates:

[email protected] | 12534134134135341
[email protected] | 12534134134135341
[email protected] | 12534134134135341

^^ How can i prevent the above while still allowing both columns to have duplicates?

CodePudding user response：

SELECT 
email,
restaurant-id
FROM 
your_table
GROUP BY 
email,
restaurant-id