I'm faced with a problem where I need to update one table based on values stored in another. However, the second table contains rows which are not relevant to the query. For example:
Table1
id | active
------------
1 | Yes
2 | Yes
3 | Yes
4 | Yes
Table2
id | type | value
--------------------
1 | date | 2011
1 | name | Glen
2 | date | 2012
2 | name | Mike
I want to read the values of type 'date' and skip name, and update table1 in the process.
I've put together the following:
UPDATE table1 a, tabel2 b
SET a.active='no'
WHERE a.id = b.id
AND b.type='date'
AND b.value='2011'
This doesn't seem to work well at all.
Any help would be great.
id is the key which joins the tables.
UPDATE table1 a, tabel2 b
SET a.active='no'
WHERE a.id = b.id
AND b.type='date'
AND b.value='2011'
Try this:
UPDATE table1
SET active = 'no'
WHERE a.id
IN (
SELECT b.id FROM table2 WHERE type = 'date' AND value = '2011'
)
This will work with a natural join
UPDATE table1
SET active='no'
WHERE id in
(
select id from table1 natural join table2
where
type='date'
AND value='2011'
)
Related
I have two tables with a VARCHAR column called "name1" and "name2":
table1:
id | name1
1 | xyz
2 | foo
3 | barfoo
4 | xchad
table2:
id | id_table1 | name2
1 | NULL | xchad
2 | NULL | foo
3 | NULL | hade
4 | NULL | bar
I want to update the column id_table1 of table2 with the respective id from table1 where the rows name1 and name2 match.
For example in table2 the first row should be updated with 4 in column id_table1 since 'xchad' = 'xchad'.
A join simply takes too much time with the string compare.
Thank you!
Consider:
UPDATE table1 t1
INNER JOIN table2 t2 ON t2.name2 = t1.name1
SET t2.id_table1 = t1.id
With indexes on table1(name1) and table2(name2), this should perform efficiently.
An alternative is to use a correlated subquery:
UPDATE table2 t2
SET t2.id_table1 = (
SELECT t1.name1 FROM table1 t1 WHERE t1.name1 = t2.id_table1
)
Please note that this second solution does require each name in table2 to have a unique match in table1.
I am trying to get different values on rows of one table, and I can't think of how to that.
Lets say for example:
table1
id | name | empCode | insCode
1 John | E101 | I101
table2
id | code | name | role
1 | E101 | Mich | 2
2 | I101 | Bran | 3
table1 has reference id of table2, and empCode and insCode in table1 dependes on code and role in table2.
What I want is like this:
id | code | name | empCode | insCode | role |
1 | ? | John | E101 | I101 | ? |
I honestly don't know if its possible to retrieve multiple rows in same table in one select query.
If its not, what other possible solutions can I go with?
There is problem in your table design but you can get as your expected with below query:
select
result1.id,
result1.code,
result1.name,
result1.empCode,
result1.insCode,
result1.role as role_of_empCode,
result2.role as role_of_insCode
from (
SELECT tbl1.id,
tbl2.code,
tbl1.name,
tbl1.empCode,
tbl1.insCode,
tbl2.role
FROM `table2` tbl2
INNER JOIN `table1` tbl1
on tbl2.code = tbl1.empCode
) as result1,
`table2` result2
where result1.insCode = result2.code
ORDER BY result1.id;
You can check in this link!
Try something like:
SELECT a.*, b.role FROM
table1 a inner join table2 b on a.id=b.id
Also you may want to consider removing empcode and inscode from table 2 since its being redundant in table 1 OR vice versa depending on what your objectives are.
There are two tables with details as mentioned below in MySQL:
TABLE 1:
+-------------+---------------+
| user_id | isactive |
+-------------+---------------+
| aaa | 0 |
+-------------+---------------+
| bbb | 0 |
+-------------+---------------+
TABLE 2:
+-------------+---------------+-----------+
|store_no | owner | store |
+-------------+---------------+-----------+
|1234 | aaa | aaa,xyz |
+-------------+---------------+-----------+
|1006 | aaa | aaa |
+-------------+---------------+-----------+
|1005 | ccc | www |
+-------------+---------------+-----------+
I need to fetch rows from table 1 whose entries are neither in 'owner' nor in 'store' column of table 2. For example, in the above scenario, the resultset should contain 'bbb'.
I tried using find_in_set, locate etc but could not fetch the details as required. Please help..
Updated Tables format
Query:
select a.user_id from table1 u
left outer join table2 a
on (owner=user_id or concat(',',store,',') like concat('%,',user_id,',%'))
where (find_in_set(user_id,owner) = 0 or find_in_set(user_id,store) = 0)
and isactive=0
FYI, store column can have concatenated values of more than one userid
You can try using NOT EXISTS
SELECT
T1.user_id
FROM TABLE_1 T1
WHERE NOT EXISTS (
SELECT 1
FROM
TABLE_2 T2
WHERE T2.owner = T1.user_id OR FIND_IN_SET(T1.user_id,T2.store) > 0
);
SQL FIDDLE DEMO
Suggestion:
Is storing a delimited list in a database column really that bad?
You can do it like following :-
SELECT * FROM table1 WHERE user_id NOT IN (SELECT owner FROM table2) AND NOT FIND_IN_SET(user_id, (SELECT store FROM table2));
Second option :-
SELECT * FROM table1 WHERE user_id NOT IN (SELECT owner FROM table2) AND FIND_IN_SET(user_id, (SELECT store FROM table2)) = 0;
It may help you.
I think this should work:
select user_id
from table1
where user_id not in
(select owner from table2)
and not find_in_set(user_id,
(select store from table2)
);
I have the following two tables:
Table A
+-------------------+
|___User___|__Value_|
| 3 | a |
| 4 | b |
| 5 | c |
|____6_____|__d_____|
Table B
+-------------------+
|___User___|__Value_|
| 1 | |
| 4 | |
| 5 | |
|____9_____|________|
My job is to take user from Table A (and their correspondings value) and then map it to Table B and insert those values in there. So from the above example Table B should look like this after running the script:
Table B
+-------------------+
|___User___|__Value_|
| 1 | |
| 4 | b |
| 5 | c |
|____9_____|________|
My question is how can I construct an SQL query that will do this for me in an efficient way, if Table A contains 300,000 + entries and Table B contains 70,000 entries?
NOTES: In Table A the User field is not unique and neither is the Value field. However in Table B, both the User and Value fields are unique and should not appear more than once. Neither are primary keys for either tables.
Could be this
update table_b as b
inner join table_a as a on a.User = b.User
set b.value = a.value
In real-world situations, it would be more likely that you want a predictable value, such as the greatest value for any given user. In that case you would want
update table_b as b
inner join (
select user, max(value) from table_a
group by user ) as a_max on a.user = b.user
set b.value = a_max.value
Your question is unclear about what to do about any values that are already in b. If you use a left join, then these will explicitly be set to NULL:
update table_b b left join
table_a a
on a.User = b.User
set b.value = a.value;
If you want to keep the existing values for non-matches, then use inner join.
Note that this might be inefficient, but should be ok if an index exists on a(user).
If you had very few users in a and lots and lots of duplicates, then you might want to aggregate a before doing the join.
Database: mysql > ver 5.0
table 1: type_id (int), type
table 2: name_id, name, is_same_as = table2.name_id or NULL
table 3: id, table2.name_id, table1.type_id, value (float)
I want to sum values, and count values in table 3 where table2.name_id are same and also include the values of id where is_same_is=name_id. I want to select all data in table3 for all values in table2.
Apologize if my question is not very clear, and if it has already been answered but I am unable to find a relevant answer. Or dont exactly know what to look for.
[data]. table1
id | type
=========
1 | test1
2 | test2
[data].table2
name_id | name | is_same_as
==============================
1 | tb_1 | NULL
2 | tb_2 | 1
3 | tb_3 | NULL
4 | tb_4 | 1
[data].table3
id | name_id | type_id | value
======================================
1 | 1 | 1 | 1.5
2 | 2 | 1 | 0.5
3 | 2 | 2 | 1.0
output:
name_id| type_id|SUM(value)
=======================================================
1 | 1 |2.0 < because in table2, is_same_as = 1
2 | 2 |1.0
I think the following does what you want:
select coalesce(t2.is_same_as, t2.name_id) as name_id, t3.type_id, sum(value)
from table_3 t3 join
table_2 t2
on t3.name_id = t2.name_id
group by coalesce(t2.is_same_as, t2.name_id), t3.type_id
order by 1, 2
It joins the table on name_id. However, it then uses the is_same_as column, if present, or the name_id if not, for summarizing the data.
This might be what you are looking for: (I haven't tested it in MySQL, so there may be a typo)
with combined_names_tab (name_id, name_id_ref) as
(
select name_id, name_id from table2
union select t2a.name_id, t2b.name_id
from table2 t2a
join table2 t2b
on (t2a.name_id = t2b.is_same_as)
)
select cnt.name_id, t3.type_id, sum(t3.value) sum_val
from combined_names_tab cnt
join table3 t3
on ( cnt.name_id_ref = t3.name_id )
group by cnt.name_id, t3.type_id
having sum(t3.value) / count(t3.value) >= 3
Here's what the query does:
First, it creates 'combined_names_tab' which is a join of all the table2 rows that you want to GROUP BY using the "is_same_as" column to make that determination. I make sure to include the "parent" row by doing a UNION.
Second, once you have those rows above, it's a simply join to table3 with a GROUP BY and a SUM.
Note: table1 was unnecessary (I believe).
Let me know if this works!
john...