I'm currently in the process of converting data, in a table, which is why I've created a new table, identical to the old one, but empty.
I've run my data converter, and I have a difference in row count.
How do I select all rows that are different from the two tables, leaving out the primary key identifier (that differs on every entry).
select * from (
SELECT 'Table1',t1.* FROM table1 t1 WHERE
(t1.id)
NOT IN (SELECT t2.id FROM table2 t2)
UNION ALL
SELECT 'Table2',t2.* FROM table2 t2 WHERE
(t2.id)
NOT IN (SELECT t1.id FROM table1 t1))temp order by id;
You can add more columns in where columns to check on more info.
Try and see if this helps.
Related
I have two table as table1 and table2 given below:
I want to have the value of only those table_name from table1 which has there id in print_table column in table 2.
I have implemented the following query but it returns only one value:
SELECT * FROM print_tabel_permission_admin WHERE id IN (select print_table from secondary)
Use FIND_IN_SET:
SELECT DISTINCT
t1.table_name
FROM table1 t1
INNER JOIN table2 t2
ON FIND_IN_SET(t1.id, t2.print_table) > 0;
Demo
You should probably move away from storing CSV data in your tables like this. Instead, break out the IDs in table2 onto separate rows. This will make your life easier.
I am trying to find all the records that are in t1 but not in t2. I know there are more records in t1 than in t2 because when I run
select count(*)
from t1;
select count(*)
from t2;
I get 21,500 records and 21,000 records respectively. But the problem is these tables are not normalized, there are no primary keys, therefore I cannot do something like this:
SELECT id FROM t1
where t1.id
not in (
SELECT t2.id
FROM t2
where t2.id is not null);
or this
SELECT t1.id, t2.id
FROM t1
LEFT JOIN t2
ON t1.id = t2.id
where t2.id is null
as both return null, as the id numbers match perfectly, there seems to be the same exact amount of ids. There must be another field which is not matching.
UPDATE
I ended up doing this:
select id, count(id)
from t1
group by id;
select id, count(id)
from t2
group by id
it gave the same amount of claim numbers and the count of times it shows up. I copied and pasted it into excel and just subtracted one count from the other and did a conditional formatting to only show the ones that are not zero and this gave me all the ids that showed up in one table more than the other. (Sloppy solution, but it was able to resolve the issue).
You have two problems. A bad database design and somehow bogus data is being inserted into your tables.
I don't know if this will work without indexes.
A left outer join should get you started (look up the syntax).
You should end up with something like:
t1.id t2.id
1 1
2 2
3 null
4 4
Try to fix the tables by adding a primary key on 'id' to both tables using MySQL:
ALTER TABLE t1 ADD PRIMARY KEY (id)
ALTER TABLE t2 ADD PRIMARY KEY (id)
What I am trying to do is join two tables, lets call them t1 and t2 on two columns. id and name, for this example. t1 will always have id and name, but t2 won't always have id and name. t1 has more columns like viewes, reports, and t2 has other columns that need to be joined. My question is, how can I show 0's for t2's columns if they don't exist?
I hav something similar to this, that joins tables only if both tables' rows have some value.
SELECT
date(t1.start_time) date,
t1.name,
t1.viewes,
t1.reports,
t2.col5,
t2.col6
from
table1 t1
left outer join table2 t2
on t2.name = t1.name and date(t2.start_time) = date(t1.start_time)
group by
1,2
order by
1 desc,
2 asc
;
I have lot's of experience with MySQL, but sometimes find that things need to be hacked to work correctly. What's your suggestion for this problem?
I'm trying to compare two tables in different databases (or looking for a best way to do this).
Table in database one:
id int(11)
lastmod int(11)
Table in database two:
id int(11)
timestamp int(11)
Both tables have matching ids (id is not unique in db1. Like one(db2) to many (db1)) and time stamps (but other columns differ). But with time, records in database two will be updated (data in one unimportant column). And now I need to find records (timestamps), comparing ids, to find which records I need to update in database one.
Problem is also with performance, because both tables have more than 5 000 000 records.
What is best way (most optimal) to find records which need to be updated?
Assuming that id is a primary key in both tables, then the following should be efficient:
select *
from db1.table t1 join
db2.table t2
on t1.id = t2.id and
t1.lastmod <> t2.timestamp
Note that this assumes two things. First, the id is unique in each table and second that the timestamp column is not NULL.
EDIT:
If the situation is that you have multiple modifications in t1 and are trying to compare the results to t2, which has only one row, then aggregate t1 first to get the most recent modification date and proceed from there:
select *
from (select t1.id, max(t1.lastmod) as lastmod
from db1.table t1
group by t1.id
) t1 join
db2.table t2
on t1.id = t2.id and
t1.lastmod <> t2.timestamp
If you are really looking for a record with more than one modification in t1, then add a having count(*) > 1 to the subquery.
I have two tables Table1 and Table2. There are 10 fields in Table1 and 9 fields in Table2. There is one common column in both the tables i.e. AdateTime. This column saves unix time stamp of user actions. I want to display records from both the tables as a single result but sorting must me according to AdateTime. Recent action should be display first. Sometimes many recent actions in Table1 but few in Table2. Vice versa is also possible. So I want to fetch combine result set from both the tables using single query. I am using PHP MySQL.
Try
SELECT t1.*, t2.*
FROM table1 t1 INNER JOIN table2 t2
ON t1.AdateTime = t2.AdateTime
ORDER BY t1.AdateTime
or (if tables are not related)
SELECT * FROM
(SELECT ADateTime, col1, col2, col3, col4 FROM table1
UNION
SELECT ADateTime, col1, col2, 1 AS col3, NULL AS col4 FROM table2) t2
ORDER by ADateTime
I would use UNION ALL with an inline view. So something like
select col1,col2,col3,col4,col5,col6,col7,col8,col9,AdateTime
from
(
select col1,col2,col3,col4,col5,col6,col7,col8,col9,AdateTime from Table1
UNION ALL
select col1,col2,col3,col4,col5,col6,col7,col8,null as col9,AdateTime from Table2
) t
order by t.Adatetime desc;
yes you can do it. you just need to join these 2 tables with a join condition. when the join condition matches for a row only that row ll be displayed then further you can write the Code for any operation. use order by AdateTime
select t1.column_1234,t2.column_1234
from t1 table1 , t2 table2
where t1.matching_column = t2.matching_column
order by t1.AdateTime;
t1.matching_column And t2.matching_column are the Primary And Foreign keys for these tables (Matching Column)