CODEWITHSUNDEEP
mysql
Ofir Hadad
Ofir Hadad

Reputation: 1900

how to replace text in cell to a data in another table in mysql

I need you help.

I have a table in MYSQL like this

*TABLE1*
id | permission
-- | ----------
a1 | 1,2,3,4,5
v2 | 2,3,4
r1 | 1,3,4,5
b4 |
h7 | 4,5

and i have another table

*TABLE2*
id | permission
-- | ----------
1  | Allow
2  | Not Allow
3  | Disabled
4  | WOW
5  | Grant

I want to select TABLE1 JOIN TABLE2 BUT: The new table should be like this

*NEW_TABLE*
id | permission
-- | ----------
a1 | Allow,Not Allow,Disabled,WOW,Grant
v2 | Not Allow,Disabled,WOW
r1 | Allow,Disabled,WOW,Grant
b4 |
h7 | WOW,Grant

Is there a way to make it in MYSQL?

Upvotes: 0

Views: 115

Answers (2)

Ivica
Ivica

Reputation: 386

well you could try something along these lines:

this is test setup:

mysql> select * from table1;
+------+------------+
| id   | permission |
+------+------------+
| a1   | 1, 2, 3, 4 |
| v2   | 2, 3, 4    |
+------+------------+
2 rows in set (0.01 sec)



mysql> select * from table2;
+------+------------+
| id   | permission |
+------+------------+
| 1    | Allow      |
| 2    | Not Allow  |
| 3    | Disabled   |
+------+------------+
3 rows in set (0.01 sec)


mysql> select id, GROUP_CONCAT(t2perm) from (SELECT t1.*, t2.id as t2id, t2.permission as t2perm from table2 t2 cross join table1 t1) crs where INSTR(permission, t2id) > 0 group by id;
+------+--------------------------+
| id   | GROUP_CONCAT(t2perm)     |
+------+--------------------------+
| a1   | Allow,Not Allow,Disabled |
| v2   | Not Allow,Disabled       |
+------+--------------------------+
2 rows in set (0.00 sec)

To explain a bit; first you cross join both tables and that should result in cartesian product, like so:

mysql> SELECT * from table2 cross join table1;
+------+------------+------+------------+
| id   | permission | id   | permission |
+------+------------+------+------------+
| 1    | Allow      | a1   | 1, 2, 3, 4 |
| 1    | Allow      | v2   | 2, 3, 4    |
| 2    | Not Allow  | a1   | 1, 2, 3, 4 |
| 2    | Not Allow  | v2   | 2, 3, 4    |
| 3    | Disabled   | a1   | 1, 2, 3, 4 |
| 3    | Disabled   | v2   | 2, 3, 4    |
+------+------------+------+------------+
6 rows in set (0.00 sec)

from that point, just select rows that have one string contained in another (INSTR(permission, t2id) => mapping permissions onto ids), you'll end up with this:

mysql> select * from (SELECT t1.*, t2.id as t2id, t2.permission as t2perm from table2 t2 cross join table1 t1) crs where INSTR(permission, t2id) > 0;
+------+------------+------+-----------+
| id   | permission | t2id | t2perm    |
+------+------------+------+-----------+
| a1   | 1, 2, 3, 4 | 1    | Allow     |
| a1   | 1, 2, 3, 4 | 2    | Not Allow |
| v2   | 2, 3, 4    | 2    | Not Allow |
| a1   | 1, 2, 3, 4 | 3    | Disabled  |
| v2   | 2, 3, 4    | 3    | Disabled  |
+------+------------+------+-----------+
5 rows in set (0.00 sec)

now just aggregate results with GROUP_CONCAT...

select id, GROUP_CONCAT(t2perm) from (SELECT t1.*, t2.id as t2id, t2.permission as t2perm from table2 t2 cross join table1 t1) crs where INSTR(permission, t2id) > 0 group by id;

Upvotes: 2

Write Down
Write Down

Reputation: 156

I suppose you have to work with cases.

But I think what you're trying to do is absolutly wrong. Why would you create such 2 tables?

Upvotes: 0

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