I have a lot of tables in my data base all with same structure. I want to select from all tables without having to list them all like so:
SELECT name FROM table1,table2,table3,table4
And I tried but this doesn't work:
SELECT name FROM *
Is there a way to select all tables in a database without listing each table in the query?
i am working on a online file browser, each directory has its own table
It is very unuseful due to one reason: when you have about 200 files (this situation is real, yeah?) you have about 200 tables. And if there are about thousand files in each directory.. etc. In some time you will either have slow processing while selecting from your database either have to buy more server resources.
I think you should change your database structure: just begin from adding parent_folder_id column to your table, after this you can put all your rows (files and directories -- because directory is a file too -- here you can add type column to determine this) into the one table.
As far as I know there are no such wildcards to select from *all tables. I would recommend writing a view and then call that view instead (it will save you writing out the names every time) – VoodooChild
That means you should not have a lot of tables with same structure at all.
But just one table with a field to distinguish different kinds of data, whatever it is.
Then select all would be no problem.
I found a solution, but I would still like to know if there is a simpler way or a better solution.
But here's what I came up with:
$tables = mysql_query("show tables");
$string = '';
while ($table_data = mysql_fetch_row($tables)){
$string.=$table_data[0].',';
}
$ALL_TABLES = substr($string,0,strlen($string)-1);
$sql="SELECT name FROM $ALL_TABLES ";
Sounds like you want to UNION together each table, so you get the results as if they were one big table. You'll need to write out the query in full like
SELECT * FROM table1 UNION SELECT * FROM table2 UNION ... SELECT * FROM tableN
Copy & paste may be your friend here.
I'm curious as to why you have lots of different tables with the same structure?
You can generate SELECT by cursor like this code
and find all result step by step in sql server:
--Author: Ah.Ghasemi
Declare #Select sysname;
DECLARE A CURSOR
FOR Select 'select ' + '*' + ' from ' + name
from sys.tables
--Where name like 'tbl%'
Order by name
OPEN A
FETCH NEXT FROM A INTO #Select
While (##FETCH_STATUS <>-1)
Begin
exec sp_executesql #Select
FETCH NEXT FROM A INTO #Select;
End
close A
Deallocate A
Please let us know if the problem is not resolved.
I hope you for the best
Related
I'm pretty new to SQL and need some help configuring a command. The details of my database structure can be found in this thread:
How to copy new data but skip old data from 2 tables in MySQL
The general problem is that I'm merging a new (temporary) database with an old one. I want to keep all the data in the old but copy over any new data from the new. If there is a duplicate, the old should be favored/kept.
My current command is:
INSERT INTO BAT_players
SELECT *
FROM bat2.bat_players
WHERE NOT EXISTS (SELECT 1 FROM BAT_players WHERE BAT_players(UUID) = bat2.bat_players(UUID));
When I run this, I get
Function bat2.bat_players undefined or Function bat.BAT_players undefined
I do not know how to proceed and would appreciate the help.
Columns are accessed using . not parens:
INSERT INTO BAT_players
SELECT *
FROM bat2.bat_players bp2
WHERE NOT EXISTS (SELECT 1
FROM BAT_players bp
WHERE bp.UUID = bp2.UUID
);
Note that the columns have to correspond by position, because you are not explicitly listing them. As a general rule, you want to list all all the columns in an insert:
INSERT INTO BAT_players ( . . . )
SELECT . . .
. . .
I am no familiar with the idea of MySQL,
I worked with SQL Server to be honest but if all the infrastructure are the same and I say IF, then there is a trick to these kinds of transactions between databases and that's simply the phrase dbo.
Like below:
using BAT
Insert into bat_players
SELECT * FROM bat2.dbo.bat_players
and also the rest of your conditions
or
instead of using the phrase using bat you can simply add the dbo to:
Insert into bat.dbo.bat_players
and again the rest of your condition,
just remember to use the dbo before each [table name].
HUGE UPDATE
if you want to access the fields (columns) you have to use . as #Gordon Linoff explained above. For example:
...
Where bat2.dbo.bat_players.UUID = --the condition--
I am porting client DB to new one with different post titles and rows ID's , but he wants to keep the hits from old website,
he has over 500 articles in new DB , and updating one is not an issue with this query
UPDATE blog_posts
SET hits=8523 WHERE title LIKE '%slim charger%' AND category = 2
but how would I go by doing this for all 500 articles with 1 query ? I already have export query from old db with post title and hits so we could find the new ones easier
INSERT INTO `news_items` (`title`, `hits`) VALUES
('Slim charger- your new friend', 8523 )...
the only reference in both tables is product name word within the title everything else is different , id , full title ...
Make a tmp table for old data in old_posts
UPDATE new_posts LEFT JOIN old_posts ON new_posts.title = old_posts.title SET new_posts.hits = old_posts.hits;
Unfortunately that's not how it works, you will have to write a script/program that does a loop.
articles cursor;
selection articlesTable%rowtype;
WHILE(FETCH(cursor into selection)%hasNext)
Insert into newTable selection;
END WHILE
How you bridge it is up to you, but that's the basic pseudo code/PLSQL.
The APIs for selecting from one DB and putting into another vary by DBMS, so you will need a common intermediate format. Basically take the record from the first DB, stick it into a struct in the programming language of your choice, and prefrom an insert using those struct values using the APIs for the other DBMS.
I'm not 100% sure that you can update multiple records at once, but I think what you want to do is use a loop in combination with the update query.
However, if you have 2 tables with absolutely no relationship or common identifiers between them, you are kind of in a hard place. The hard place in this instance would mean you have to do them all manually :(
The last possible idea to save you is that the id's might be different, but they might still have the same order. If that is the case you can still loop through the old table and update the number table as I described above.
You can build a procedure that'll do it for you:
CREATE PROCEDURE insert_news_items()
BEGIN
DECLARE news_items_cur CURSOR FOR
SELECT title, hits
FROM blog_posts
WHERE title LIKE '%slim charger%' AND category = 2;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN news_items_cur;
LOOP
IF done THEN
LEAVE read_loop;
END IF;
FETCH news_items_cur
INTO title, hits;
INSERT INTO `news_items` (`title`, `hits`) VALUES (title, hits);
END LOOP;
CLOSE news_items_cur;
END;
It is possible?
DECLARE #vTableName varchar(50)
SET #vTableName = (SELECT TableName FROM qms_Types WHERE Id = 1)
SELECT * FROM #vTableName
I have this error:
Msg 1087, Level 16, State 1, Line 3 Must declare the table variable
"#vTableName".
Short answer: No.
Long answer: Noooooooooooooooooooooooooooooooooooooo. Use dynamic SQL if you have to, but if you're structuring your tables in a way where you don't know the table name ahead of time, it might benefit you to rethink your schema.
Here is a great resource for learning how to use dynamic SQL: The Curse and Blessings of Dynamic SQL
if you're trying to select from a table of that name, then you can do something like this:
DECLARE #vTableName varchar(50)
SET #vTableName = (SELECT TableName FROM qms_Types WHERE Id = 1)
EXECUTE('SELECT * FROM [' + #vTableName + ']')
my solution for this:
EXECUTE('SELECT * FROM ' + TableName + '')
It seems as though different folks are interpreting the OP differently.
I'm pretty sure the OP is asking for this type of concept / ability / maneuver...
"Put a table name into a variable and then use that variable as though it were a table name."
DECLARE #TableIWantRecordsFrom varchar(50)
-- ^^^^^^^^^^^^^^^^^^^^^^
SET #TableIWantRecordsFrom = (SELECT TableName FROM qms_Types WHERE Id = 1) -- (L1)
-- ^^^^^^^^^^^^^^^^^^^^^^
-- Let's say, at this point, #TableIWantRecordsFrom ... contains the text 'Person'
-- ^^^^^^^^^^^^^^^^^^^^^^
-- assuming that is the case then...
-- these two queries are supposed to return the same results:
SELECT top 3 fname,lname,mi,department,floor FROM Person
-- ^^^^^^
SELECT top 3 fname,lname,mi,department,floor FROM #TableIWantRecordsFrom -- (L2)
-- ^^^^^^^^^^^^^^^^^^^^^^
From reading all the responses and answers, it appears that this kind of maneuver can't be done - unless - you use dynamic SQL which...
can be a bit of a pain to create and maintain and
can be more work to create than the time it "saves" you in the future.
================================================================
There are other languages where this can be done... in literally, two lines of code (see (L1) and (L2) in above code) and not having to do a lot of formatting and editing.)
(I've done it before - there is another language where all you'd need is L1 and L2...)
================================================================
It is unfortunate that SQL Server will not do this without going to a decent amount of effort...
first write your SQL then
test it to make sure it does, in fact, work then
frame each line with tick marks and then escape your ticks that are now inside THOSE tick marks
declare the variable
set the variable to the sql statement you ticked above
(I may be missing some additional steps)
Oh, and then, if you ever need to maintain it
you need to either, be very careful and just edit it right there, as is, and hope you get it all just right -or- you may have saved a copy of it... un-ticked and un-variablized so you can edit the "real" sql and then when you're done you can RE DO these steps... again.
I think you want this:
DECLARE #vTableName table(TableName varchar(50))
insert into #vTableName
SELECT TableName FROM qms_Types WHERE Id = 1
SELECT * FROM #vTableName
The only way you can do this is through Dynamic SQL which refers to the practice of creating a T-SQL text and executing it using the sp_executesql (or simply exec)
Here is a helpful link about dynamic sql The Curse and Blessings of Dynamic SQL.
You should really think whether or not this is a case for dynamic sql or if there is another way for you to perform this operation.
I'm trying to implement a facebook search in my system (auto suggest while typing).
I've managed to code all the ajax stuff, but I'm not sure how to query the database.
I've created a table called People which contains the fields: ID, FirstName, LastName, MiddleName, Email.
I've also created a FTS-index on all those fields.
I want to create a stored procedure that will get as a parameter the text inserted in the query box and returns the suggestions.
For example, When I will write in the textbox the query "Joh Do"
It will translate to the query:
select * from People where contains(*, '"Joh*"') and contains(*, '"Do*"')
Is there a way to do that in stored procedure?
P.S
I've tried to use the syntax
select * from People where contains(*,'"Joh*" and "Do*"')
but it didn't returned the expected results, probably because it needs to search the words on different fields. Is there a way to fix that?
Thanks.
Try
select *
from People
where (FirstName Like '%'+ #FirstName + '%') and
(MiddleName Like '%'+ #MiddleName + '%') and
(LastName Like '%'+ #LastName + '%')
Also you may want to restrict the results to only return a maximum of say 10 by using:
select top 10
EDIT 1:
OK I now understand the problem better. I would use dynamic sql thus:
First create a split function e.g. Example Split function using XML trick
Then use dynamic sql:
declare #tstr varchar (500)
set #tstr = ''
select #tstr =#tstr + ' Contains(*, ''"'+ val + '*")' + ' and '
from dbo.split(#SearchStr, ' ')
set #tstr = left(#tstr,len(#tstr)-4)
select #tstr
Declare #dsql as varchar(500)
set #dsql = 'select * from People where '+ #tstr
exec (#dsql)
Also please note as per Remus, be aware of SQL Injections, the use of sp_executesql (instead of EXEC) would be better.
The problem is the open list nature of the argument. I can be Joh, it can be Joh Do, it can be Joh Do Na and so on and so forth. You have two main alternatives:
parse the input in the web app (in ASP I assume) and then call an appropriate procedure for the number of entries (ie. exec usp_findSuggestions1 'Joh', exec usp_findSuggestions2 'Joh', 'Do', exec usp_findSuggestions1 'Joh', 'Do', 'Na'). The first procedure uses 1 contains, the second has 2 contains .. and contains ... and the last has 3. This may look totally ugly from a DRY, code design and specially code maintenance pov, but is actually the best solution as far as T-SQL is concerned, due primarily to the plan stability of these queries.
pass the input straight into a single stored procedure, where you can split it into components and build a dynamic T-SQL query with as many contains as necessary.
Both solutions are imperfect. Ultimately, you have two problems, and both have been investigated before to quite some depth:
the problem of passing a list to a T-SQL procedure. See Arrays and Lists in SQL Server 2005 and Beyond
the problem of an undetermined number of conditions in the WHERE clause, see The Curse and Blessings of Dynamic SQL
The AJAX Toolkit has the "AutoComplete" control that provides this functionality out of the box. It is very simple to use.
Look at a sample here
The following doesn't work, but something like this is what I'm looking for.
select *
from Products
where Description like (#SearchedDescription + %)
SSRS uses the # operator in-front of a parameter to simulate an 'in', and I'm not finding a way to match up a string to a list of strings.
There are a few options on how to use a LIKE operator with a parameter.
OPTION 1
If you add the % to the parameter value, then you can customize how the LIKE filter will be processed. For instance, your query could be:
SELECT name
FROM master.dbo.sysobjects
WHERE name LIKE #ReportParameter1
For the data set to use the LIKE statement properly, then you could use a parameter value like sysa%. When I tested a sample report in SSRS 2008 using this code, I returned the following four tables:
sysallocunits
sysaudacts
sysasymkeys
sysaltfiles
OPTION 2
Another way to do this that doesn't require the user to add any '%' symbol is to generate a variable that has the code and exceute the variable.
DECLARE #DynamicSQL NVARCHAR(MAX)
SET #DynamicSQL =
'SELECT name, id, xtype
FROM dbo.sysobjects
WHERE name LIKE ''' + #ReportParameter1 + '%''
'
EXEC (#DynamicSQL)
This will give you finer controller over how the LIKE statement will be used. If you don't want users to inject any additional operators, then you can always add code to strip out non alpha-numeric characters before merging it into the final query.
OPTION 3
You can create a stored procedure that controls this functionality. I generally prefer to use stored procedures as data sources for SSRS and never allow dynamically generated SQL, but that's just a preference of mine. This helps with discoverability when performing dependency analysis checks and also allows you to ensure optimal query performance.
OPTION 4
Create a .NET code assembly that helps dynamically generate the SQL code. I think this is overkill and a poor choice at best, but it could work conceivably.
Have you tried to do:
select * from Products where Description like (#SearchedDescription + '%')
(Putting single quotes around the % sign?)
Dano, which version of SSRS are you using? If it's RS2000, the multi-parameter list is
not officially supported, but there is a workaround....
put like this:
select *
from tsStudent
where studentName like #SName+'%'
I know this is super old, but this came up in my search to solve the same problem, and I wound up using a solution not described here. I'm adding a new potential solution to help whomever else might follow.
As written, this solution only works in SQL Server 2016 and later, but can be adapted for older versions by writing a custom string_split UDF, and by using a subquery instead of a CTE.
First, map your #SearchedDescription into your Dataset as a single string using JOIN:
=JOIN(#SearchedDedscription, ",")
Then use STRING_SPLIT to map your "A,B,C,D" kind of string into a tabular structure.
;with
SearchTerms as (
select distinct
Value
from
string_split(#SearchedDescription, ',')
)
select distinct
*
from
Products
inner join SearchTerms on
Products.Description like SearchTerms.Value + '%'
If someone adds the same search term multiple times, this would duplicate rows in the result set. Similarly, a single product could match multiple search terms. I've added distinct to both the SearchTerms CTE and the main query to try to suppress this inappropriate row duplication.
If your query is more complex (including results from other joins) then this could become an increasingly big problem. Just be aware of it, it's the main drawback of this method.