I'm trying to create a mysql table from the inner join between two other tables. I'm dealing with a database someone creates which has the following tables:
sitematrix_sites
sitematrix_databases
They are related by another table (I don't know why don't use a foreign key) called sitematrix_sites_databases which has the following fields:
site_id and database_id.
That's how the two tables relate. Now I'm trying to remove that to make my life easier, so I have:
mysql> CREATE TABLE result AS(select * from sitematrix_databases INNER JOIN site
matrix_site_databases ON sitematrix_site_databases.database_id = sitematrix_data
bases.database_id);
ERROR 1060 (42S21): Duplicate column name 'database_id'
However, I'm getting that error. Does someone know how can I merge the two tables without repeating the database_id field?
Thanks
Remove the * in your SELECT statement and actually list out the columns you want in your new table. For columns that appear in both original tables, name the table as well (e.g. sitematrix_databases.database_id).
Don't use * instead name each column and use aliases. For instance instead of sitematrix_database.database_id you can have alternativeName. Also you can pick and choose which columns you want this way as well.
In SQL Server, you can use "select into". This might be equivalent syntax for mySql:
http://dev.mysql.com/doc/refman/5.0/en/ansi-diff-select-into-table.html
Unfortunately, it's a two commands (not just one):
http://www.tech-recipes.com/rx/1487/copy-an-existing-mysql-table-to-a-new-table/
CREATE TABLE recipes_new LIKE production.recipes; INSERT recipes_new SELECT * FROM production.recipes;
Instead of using SELECT * ... try SELECT database_id ...
MySQL does not like joining tables that have the same column name.
Related
I want to use multiple database because I have 1 database which contain 40 tables and it doesnt seem good.Thats why I want to create another database but problem is I am not able to join this databases at one query for example
I have 'core' database and it contains users table which has user_id column
second database is post database and I need get user_id from users table which is in 'core' database like below
SELECT post_message from posts where 'core'.user_id=123
is that possible?or should I stick with one database?I have also foreign key problem which is related with database relation.
If it is SQL SERVER Product, You can call the Object residing on another DB like below
SELECT * FROM [DB_NAME].[Schema_Name].[Table_NAME]
For Example:
SELECT * FROM DB1.dbo.Employee
For MySQL : Please go through the below ans
Select columns across different databases
I have 2 tables. suppose a & b
a has id, name, roll. b has id,group,name
This name column data are not same. How can I select and uniquely identify them?
I know about
SELECT a.id,a.name,a.group FROM a,b ............
I know this. But this is an example. I am working with huge amount of data with 20-30 columns in each table. So I don't want to write the column names I need to select rather I want to write the names that I want to exclude.
Like
SELECT * Except b.name............
OR is there any way to uniquely identify after join. Like
.......... a,b WHERE a.name as name1
Please don't ask why those column names are same. I admit it was a mistake. But it's already implemented and heavily used. So finding another way. Is there any simple way to exclude a column while merging them?
Well, you can't write the names you wish to exclude. That is not how SQL works.
However, if writing out 20-30 column names is that much of a burden, you can use information_schema.columns. I write it that way, because 20-30 column names is not particularly large and writing them out is probably less effort than writing the question.
But, back to the solution. It looks something like this:
select concat(c.column_name, ' as ', 'a_', column_name, ', ')
from information_schema.columns c
where table_name = 'a' ;
You might want to include the table schema as well.
As an IDEA, what you can do is, if you want to avoid columns of specific table & your statements have multiple table, you can try following,
Suppose you have 20 columns in table a & 5 columns in table b, you want to avoid col2,col3 & col4 of table b. Standard method is that you should write name of all columns of table a & required columns of table b. But you can avoid to write long list of 20 columns of table by writing a.* & then type required columns of table b. Please see below statement.
Select a.*,b.col1,b.col4,b.col5 from a,b
But if you require to exclude some columns from both table, then I think there is no other way than writing all required column names from both table.
There is no way to exclude a column in SQL SELECT Statement, you can only select a column. You can give alias name to columns while selecting them like below, so that you can identity columns using those alias names.
SELECT a.id as [column1],a.name as [column2],a.group as [column3] FROM a,b ............
There is no way to exclude a specific column but you can avoid to write all columns name and easy your job by below steps-
Step1: Execute below query-
SELECT a.*,b.* FROM a,b ............limit 1;
Step2: Export it into csv format with headings.
Step3: Copyp first (heading) row from csv.
Step4: Delete columns, those are not required and use other columns in your query.
There's only one waY i could see-
first create a temorary table
CREATE TEMPORARY TABLE IF NOT EXISTS mytable
(id int(11) NOT NULL, PRIMARY KEY (id)) ENGINE=MyISAM;
then put your column in temporary table-
SELECT * INTO mytable
FROM YourTable
/* Drop the cloumns that are not needed */
ALTER TABLE mytable
DROP COLUMN ColumnToDrop
/* Get results and drop temp table */
SELECT * FROM #TempTable
DROP TABLE #TempTable
I am building a site and i need to retrieve some information. I have this query.
$SQL = "SELECT distretto_108, provinca_113, regioni_116, tipologia_pdv_106,
richiesta_ccnl_107, coop_va_109, nome_pdv_110,
indirizzo_pdv_111, localita_112
FROM civicrm_value_informazioni_su_tute_le_schede_p_22 ";
I need to add this other code:
WHERE civicrm_event.title_en_US='".addslashes($_GET["titles"])."'
but it's not working...
i need to compare let's say the id of another table with the id of the current table... How to do that?
Thanks in advance...
You should learn something about joining tables...
Do not know what the relation is between the two tables (simply said: what column from one table is pointing to what column at other one), but try something similar (modification needed to meet You DB structure) - now lets assume both tables have related column called event_id:
$SQL = "SELECT distretto_108, provinca_113, regioni_116, tipologia_pdv_106,
richiesta_ccnl_107, coop_va_109, nome_pdv_110,
indirizzo_pdv_111, localita_112
FROM civicrm_value_informazioni_su_tute_le_schede_p_22 cvistlsp22
LEFT JOIN civicrm_event ce ON ce.event_id = cvistlsp22.event_id
WHERE ce.title_en_US='".mysql_real_escape_string($_GET["titles"])."'";
civicrm_value_informazioni_su_tute_le_schede_p_22 table name is very long and You will not be able to create a table with such long name in other DBMS (e.g. ORACLE), so try to make it shorter while still self-describing...
If You want to join tables they have to have a relation, read more about relations and how to use them here: http://net.tutsplus.com/tutorials/databases/sql-for-beginners-part-3-database-relationships/
You are retrieving the data from table civicrm_value_informazioni_su_tute_le_schede_p_22 in your query while the where clause you are adding, refers to the table civicrm_event. You need to add this new table in the from clause and do a join among the two tables using some common key. Example below:
$SQL = "
SELECT distretto_108, provinca_113, regioni_116, tipologia_pdv_106, richiesta_ccnl_107, coop_va_109, nome_pdv_110, indirizzo_pdv_111, localita_112
FROM civicrm_value_informazioni_su_tute_le_schede_p_22
JOIN civicrm_event ON civicrm_value_informazioni_su_tute_le_schede_p_22.ID_PK = civicrm_event.ID_FK
WHERE civicrm_event.title_en_US='".addslashes($_GET["titles"])
";
You need to replace the ID_PK and ID_FK with the relevant Primary and Foreign Keys that bind the tables together.
Please note using query params like that is not recommended. Please read PHP Documentation here for more explanation.
If I have two tables in a MySQL database that both have a column called order_number, given an order_number value but not knowing which table it comes from how would I go about setting up a query that would return the name of the table it was found in?
I am particularly interested in the name of the table so I can set up subsequent updates to that table.
Also, I am using PHP for the handling of the query.
select "tableA" as tableName,order_number from tableA where order_number=5
UNION
select "tableB" as tableName,order_number from tableB where order_number=5;
I had my query set up the other day as so
$query = "SELECT card_id,title,description,meta_description,seo_keywords,price
FROM cards,card_cheapest order by card_id";
As you can see, I was selecting card_id,title,description,meta_description,seo_keywords from the table cards, and price was coming from cheapest_card. They both have the card_id in common (in both tables). However, I ran into a bit of an issue. When I run the query in navicat lite, I receive an error "card_id is ambiguous". Was I doing something wrong?
When 2 or more tables have a column that is named the same, you have to qualify the table you want the column to be from.
i.e.:
$query = "SELECT cards.card_id,title,description,meta_description,seo_keywords,price
FROM cards,card_cheapest order by card_id";
Furthermore, do you really want to run the query this way, without a WHERE/JOIN-clause to define how to JOIN the two tables?
$query = "SELECT cards.card_id,title,description,meta_description,seo_keywords,price
FROM cards,card_cheapest WHERE cards.card_id = card_cheapest.card_id
ORDER BY card_id";
When you have the same column name in two tables you're selecting from, you have to prefix the part in the SELECT with one of the table names (it doesn't matter which if it's the same data)
such as SELECT cards.card_id, ...
EDIT: However, cularis's answer is much more explanatory than mine, and take note about joining the two card_id columns if you want to get correct results.
When you run queries that get information from multiple tables with shared field names you need to specify from which table you want to extract what field. You do this by specifying the table name before the field name.
In your case you have two options:
cards.card_id or card_cheapest.card_id.
Also I agree with #cularis, you are probably better of doing a join, but still you will need to specify which card_id you want to select: the one from cards or card_cheapest.