MySQL：从相关表中获取数据

Question

I'm looking for help with acquiring and displaying information from related tables in MySQL. I have two tables:

1. "table1" with columns id, name, surname
2. "table2" with columns id, phone

They are related by the id columns.

I'm trying to display the name, surname and phone together. What I'm currently using is:

SELECT name, surname, phone FROM table1, table2 WHERE table1.id = table2.id

However, I feel like I'm not using the relationship between the tables properly as I believe this would work between unrelated tables as well.

Also, not every id from table1 has a record in table2, meaning not everyone has a phone number. The method above results in only showing those id's that exist in both table1 and table2, while I want to display the data of those without a phone number as well, either by a blank space or a "N/A" in the phone column.

Any tips on how to properly display the data are greatly appreciated.

Answer 1

You need to use an LEFT OUTER JOIN statement to join the two tables together. LEFT OUTER JOIN will still show records from table1 even if there is no matching id in table2 . Something like:

SELECT
    table1.name,
    table1.surname,
    table2.phone
FROM table1
LEFT OUTER JOIN table2
ON table1.id = table2.id

More info: https://www.w3schools.com/sql/sql_join_left.asp