MySQL选择一个字符串，如果匹配则左键联接

Question

I am trying to do something like this:

SELECT  'dave' AS fn
, lastname AS ln
, recordnumber as rn
LEFT JOIN addresses
ON firstname LIKE CONCAT( fn, '%')
order by lastname

The goal is to always get the names, and get a recordnumber IF there is a match.

The above query does not work in MySQL.

The goal is to try to match records from a list, but I need to know the misses as well as the hits on the match.

Answer 1

I think you are missing the from table here.

SELECT  'dave' AS fn, 
lastname AS ln, 
recordnumber as rn
FROM table1 t1 left 
OUTER JOIN addresses a1 on a1.name=t1.name
WHERE t1.firstname LIKE CONCAT(fn,'%')
ORDER BY lastname

a1.name=t1.name --- you have to find this foreign key relation between your tables to join these two tables.