CREATE TABLE bar LIKE foo;
INSERT INTO bar (id,user,first,last)
(SELECT f.id,CONCAT(SUBSTRING(f.first,1,1),f.last,
(SELECT COUNT(*) FROM foo f2
WHERE SUBSTRING(f2.first,1,1) = SUBSTRING(f.first,1,1)
AND f2.last = f.last AND f2.id <= f.id
)),f.first,f.last from foo f);
DROP TABLE foo;
RENAME TABLE bar TO foo;
Esto se basa en una clave principal id , por lo que para cada registro insertado en bar , solo contamos los duplicados encontrados en foo con id menor que bar.id .
Dado foo:
select * from foo;
+----+------+--------+--------+
| id | user | first | last |
+----+------+--------+--------+
| 1 | aaa | Roger | Hill |
| 2 | bbb | Sally | Road |
| 3 | ccc | Fred | Mount |
| 4 | ddd | Darren | Meadow |
| 5 | eee | Sharon | Road |
+----+------+--------+--------+
El INSERT anterior s en bar , resultando en:
select * from bar;
+----+----------+--------+--------+
| id | user | first | last |
+----+----------+--------+--------+
| 1 | RHill1 | Roger | Hill |
| 2 | SRoad1 | Sally | Road |
| 3 | FMount1 | Fred | Mount |
| 4 | DMeadow1 | Darren | Meadow |
| 5 | SRoad2 | Sharon | Road |
+----+----------+--------+--------+
Para eliminar el "1" al final de los nombres de usuario,
INSERT INTO bar (id,user,first,last)
(SELECT f3.id,
CONCAT(
SUBSTRING(f3.first,1,1),
f3.last,
CASE f3.cnt WHEN 1 THEN '' ELSE f3.cnt END),
f3.first,
f3.last
FROM (
SELECT
f.id,
f.first,
f.last,
(
SELECT COUNT(*)
FROM foo f2
WHERE SUBSTRING(f2.first,1,1) = SUBSTRING(f.first,1,1)
AND f2.last = f.last AND f2.id <= f.id
) as cnt
FROM foo f) f3)
