MYSQL :: Check Table For An Entry?

Check If An Entry Exists
I have a table which records information on ratings that each user has given each movie, it looks a little like this:

Table = USER_VOTES

USER_ID MOVIE_ID VOTE
1 2 5
2 3 5
3 4 5
3 5 5
4 3 5

I an using a simple SELECT command to find if a user has already voted, ie. if a row already exists with their USER_ID and MOVIE_ID. I am having a little trouble with this SELECT statement and wonder if there is a better way of doing this simple check. My code looks like this:

$sql = "SELECT vote FROM user_votes WHERE movie_id='$id' && user_id='$usrID'";
if ($result = mysql_query($sql, $db)) {
//if vote already exists display error
$error = "You have already voted for this moive
(your rating was ".mysql_result($result,0,"vote").").";
} else {
//if no vote exists process vote...
}

If a user has not voted before I get an error like this:
Unable to jump to row 0 on MySQL result index 2

To me it appears that mysql_query() does not return false when no results are found. Is there a command which does check results and return false or is there a much easier way to check, perhaps there could be some checking code in the actual SQL query?

Strange Results When Trying To Do A Duplicate Entry Check
My goal with this is to check a database for duplicates using the first 25 characters of the "title" column in a database called "jos_content." The query should find the entries whose titles appear more than once and then the second part should take those entries and mark them for trash (state=-2 is trash).

CREATE TEMPORARY TABLE dupes
SELECT Left(title,25)
FROM jos_content
GROUP BY title
HAVING COUNT(*)>1; # Affected rows: 4

UPDATE jos_content
SET state="-2"
WHERE (title) IN (SELECT Left(title,25) FROM dupes); # MySQL returned an empty result set (i.e. zero rows).

The result for the first part finds entries but I suspect they aren't duplicates becuase the second part returns zero entries. The actual database has about 16 duplicate rows based on the first 25 characters of the title column.

Check Table And Repair Versus Optimize Table
I am confused about the difference between running a CHECK table and REPAIR(if necessary) versus running an OPTIMIZE table. It's not very clear in the documentation, but seems that OPTIMIZE table does a check and repair in addition to the other functions performed by optimize.

I have inherited some legacy code that does a check and repair and optionally follows it with an optimize. That seems redundant to me and I would like to streamline the code to make it an "either-or" selection.

How To Check For Date/time Ranges Within Record (check For Schedule Conflicts)
You want to check scheduling conflicts and you have a record like:

appointments(table):
apptID
beginningDate
endingDate
beginningTime
endingTime

It's easy enough to check if a time is within that record. Say you want to
check if 8:00am to 10:00am is available, you would use this:

SELECT apptID
FROM appointments
WHERE (beginningDate = '2006-01-19' OR endingDate = '2006-01-19')
AND ('08:00:00' BETWEEN beginningTime AND endingTime
OR '10:00:00' BETWEEN beginningTime AND endingTime)

BUT, what if you have an all-day appointment (8:00am to 5:00pm) and there
exists an appointment already scheduled from 10:00am to 11:00am. The above
query would not find it.

Another question is what if the appointment is more than two days. Say, it's
from Monday - Wednesday from 8am to 5pm. The above query would not
successfully catch it if you wanted to schedule an appointment on Tuesday.

(I might be able to generate a date range using PHP, don't know if that's
the best way)

Check If A Table Has Been Updated
I'd like to find a way to check if any modifications has been made to a table. I'm using mysql 4.1. I'm trying to find the least resource intensive method of doing this.

Check If Table Exsists
Am creating an install.php page to create the tables for a database. After running the code I want to make sure the tables were created, how do you check is a table exsists in mysql?

Check If A Table Exists
is there any way to check if a table exists in mysql? i am using a graph program in vb, but if the table it is trying to graph doesnt exist it breaks down! i need some sort of check so as the offending table will not be added to the query if it doesnt exist?

Check Empty Table In Where Clause?
the following where clause (expurgated) suits my needs right up until the table emailman is empty (which it frequently is) and then it returns an empty set (which is bad;-)
this is actually an AND emailman... but don't I think the rest is relevant.

WHERE emailman.related_id != contacts.id How can I modify this to allow for emailman to be empty? Something like...

AND (emailman.related_id != contacts.id || NOT EXISTS (emailman.id) )

How To Check Empty Columns In A Table
If i press a button, i have to check if certain columns(fields) in a table are empty.If they are empty, i want to send an e-mail to the e-mail address which is already in this table.If there are no empty columns, then i want to do some calculation using another table.

How Do I Check If An Table Index Exists Via PHP ?
I was wondering if it's possible to verify if an table index already exists or not? As it's possible to add indexes multiple times.

Check If Row Exists In Anotehr Table
Is there a way to check if a certain value exists in another table without using something like

SELEC * FROM tbl WHERE someid = 'somevalue';

and seeing if it returns false

I ask this because I'm running a kind of search query where it selects all records from a table where this field is this, that field is that, etc.

So for example

SELECT * FROM members WHERE id='this' || name='that' || height='67' || etc..etc...

now one of the attributes is a zip code.

In another table, i just ahve a list of like a billion zip codes. Ifi want to check if the zip code exists in this list in this other table, how would i do so while preservingn the above format in one call?

Check Table Wildcard Syntax?
I need to do CHECK TABLE on a lot of tables (actually on all tables in
several databases), and hoped to do something like

mysql> CHECK TABLE reports.*

which ddn't work. The only thing that seems to work is using
cut'n'paste (or some scritpting) to get a comme seperated list. Is
there really no "smart" way of doing this?

Pulling Out The 2nd Entry From A Table
i have an application already installed. It has an table to handle attachments to articles. The structure is;

attachment_id |question_id| file_path

Is it possible to pull out the 2nd entry in a table for a particular question (using its question_id)?

eg something like?
Select * From attachments WHERE question_id = $question_id Limit ROW 2

Ive search the mysql online manual but im getting really lost!

Deleting An Entry From A Table?
When the user logs out, it doesn't display an error message, but when I check the table Currentusers, they are still on it.

$username = $_SESSION['username'];

mysql_query("DELETE FROM Currentusers WHERE username=$username");
echo $username;
echo " is now logged out.";

I must be defining the WHERE username=$username"); part incorrectly because when I take out username=$username"); and replace it with username='Jane'); it removes Jane from the table. There isn't a problem with the $username variable because it displays the value correctly. What am I doing wrong?

Alter Table Entry
What I want to do is change the value of the column "hits" from the table "stats" where the column "page" equals the variable $page. In MYSQL talk, I want to change:

SELECT `hits` FROM `stats` WHERE `page` = $page

I want to change that value to 23. How do I do this.

Getting A Random Entry From A Table
Assume I have a table with 100 entries
I would like to run a query that will return a random entry from all those that match some condition

One way would be to run the query, getting ALL the entries that match the condition and then pick one of the randomly

Is there a way to tell MySQL to do it for me, so I won't have to pick the random entry myself?
This will reduce the size of result set from n to 1.

Unique Entry In A Table
I am having a problem with trying to work out how I could select the lowest unique number in a field called MONEY. I am trying to find the record with the least money, but no other record in that table can have the same amount of money.

Here is the table:

CREATE TABLE lubidEntries (
partnerid smallint(5) unsigned NOT NULL default '0',
lubidCamp smallint(5) unsigned NOT NULL default '0',
keyword varchar(40) NOT NULL default '',
MONEY varchar(40) NOT NULL default '',
status enum('current','old', 'lubid') default NULL,
time datetime NOT NULL default '0000-00-00 00:00:00',
numberid int(10) unsigned NOT NULL default '0',
KEY lubidentries (partnerid,status,numberid)
) TYPE=MyISAM;

Check Table Command - When To Use Which Checking Option
I'm trying to decide which check table option to use for a DB-health-check script for my product. This script is to be run periodically to find and repair damaged tables. My product uses only MySQL, i.e. it does not interact with another DB. I need to find the check table option that would find damaged tables with the highest possible performance.

The 13.5.2.3 CHECK TABLE Syntax documentation states the following:
MEDIUM Scan rows to verify that deleted links are okay. This also calculates a key checksum for the rows and verifies this with a calculated checksum for the keys.

What are they referring to with the word "links"? Are they talking about links to MS Access tables? How do I know if my tables have links? Does the MEDIUM option scan rows only to check deleted links? If so, if I don' t have "deleted links", should I not use this option? By running in MEDIUM mode, will the tables be locked while "check table" is working?

For the other options - CHANGED, FAST, QUICK - will "check table" lock the tables? What access do I have to the tables while check table is running?

Duplicate Key Entry On InnoDB Table
I have a table that contains a primary key, designated as VARCHAR (1). I cannot enter the same letter of the alphabet, using lower and upper case, to create 2 entries. For example, 'A', and 'a', both cannot be specified as primary keys.

Delete Duplicate Entry From A Table
I have a question about delete command: I have to delete duplicate entry from a table and I think I have to use the following statement:

delete from ip_siti_gbw where data_evento in (
select data_evento
from ip_siti_gbw
group by data_evento
having count (data_evento ) > 1
)

When I execute I get an error about count function: FUNCTION statistiche.count does not exist

Can I use count function into a subquery such this?

How Do You Enter An Entry With A Newline Inside The Entry?
I'm trying to enter an entry into the table. However, my entries must have newlines inside each entry. Further more, i'm trying to do this from an excel file(ie. first by saving it to a text file and then using LOAD DATA INFILE..).

MySQL SELECT Table From $_POST Entry?
Is it possible to use the results of $_POST['selectTable'] from a dynamically populated drop down menu to specify the table in a MySQL SELECT query?

I want to get the user of my webpage to select which database table to use from a menu before I make a connection to the database table and retrieve the information I need. I'm assuming this is best done over two pages or using an IF ELSE routine?

Dadabase Table Field [eg 1st Row 4 Th Col] An Entry [image Or Url]
How I add to a dadabase table field [eg 1st row 4 th col] an entry [image or url] ?

Mysqlimport: Error: Duplicate Entry '2' For Key 1, When Using Table: Analysis
I am installing some databases on the mysql databases of my mac osx
10.2.8 but when I do "mysqlimport -u X -p W (directory) *.txt.table" I
am getting this answer:

mysqlimport: Error: Duplicate entry '2' for key 1, when using table:
analysis (analysis: one of the txt.table files). This problem happen
just with one sery of files that I downloaded; any other files of the
same style are having this problem.

Is this clear enough to have a solution to my problem?

Create Table Error. #1064 - You Have An Error In Your SQL Syntax; Check The Manual That Corresponds
I have been trying to create two tables with the SQL below. I have the SQL in file and tried to import it to PhpMysqlAdmin in my control panel. The wierd thing is that the first table gets created while the second one is not created and error is thrown instead. The error message is

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ....

Check Query Please
This is giving me an mysql error. Why?

DELETE FROM subscribers,list_subscribers WHERE subscribers.id = list_subscribers.ls_sub_id AND list_subscribers.ls_list_id = 1

Check 366 Day Expiration
Needing to filter on a datetime col Mplan.Start having runtimes of 366 days:

roughly:
SELECT *
FROM Plan
WHERE (CURRENT_DATE () <= Plan.Start + 366 days)

should dates be formatted 1st?

...WHERE DATE_FORMAT(Plan.Start ,'%Y%m%d') >= DATE_FORMAT(CURRENT_DATE(),'%Y%m%d' + ?)

problem with the following is that all future dates are included, as mysql manual states (which can't be included in this application):

...WHERE CURDATE() <=DATE_ADD(Start,INTERVAL 366 DAY)

2 + 7 = 11. Let's Check It... Iterating
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Numeric Check
I am looking for some function that tests if a value is numeric. I could not
find a function for this.

At the moment I am using "WHERE CONV(myfield,10,10)!=0" but I suppose there
must be a better way.

Check Constraint
does mySQL provide Check Constraint?

I try this :
alter table city add check(id>0);

It runs without error but when i tried to insert a city name with id = 0 the query runs ok. the check constraint fail to work.

oh ya, what is the syntax to see all the check constraint on a table?

CHECK Command
Could I use the check command to see if a certain identifier will never exceed a default value when data is put into the table.

capacity INTEGER NOT NULL DEFAULT 10,
CHECK(capacity<=10)

SQL To Check For A File?
I have a field in my DB that was pre-populated with a filename for each record. This filename is a picture that then shows up on the website. Problem is not all the pictuers are up yet so they wonderful red X shows instead for ones with no pictures.

We do have it setup so that if there is no picture file specified, it just shows a default "No Image" wording.

So, since all the records already have a filename in them, is there any way with SQL to have it go through the records, check what's in the image field, then see if that file exists or not? THen if it does, great, if it doesn't it would delete the value from the field?

Check For Existing Row ?
How do I determine if a row already exists ?

// see if a row has id=100

$id=100;
$query="SELECT * FROM mytable WHERE id=$id";
$result=mysql_query($query);

...what do I check now ?

User Check
I have been playing about with a website of mine. I was wondering when using mysql, how do i check if a username & email address is already being used.

CHECK Syntax
I have a table as follows:

CREATE TABLE country
(
codeCHAR(2)NOT NULL,
...
...

CHECK (CHAR_LENGTH(code) == 2)
);

The entry for 'code' MUST be two characters long. Although CHECK is not
yet implemented by mySQL, is the above syntax correct?

Secondly, the entry for 'code' MUST not contain any numbers. What is
the syntax to check for that?

Currently I am doing the checking before inserting the data but would
like to implement it in the database too.

Duplicate Check
I have a table with two columns, T1(id,info). I'd like to add some data from another table which also has two tables T2(id,info).

I have to add data from T2 into T1, but i have to check if the data already exists. Until now i did like this : select info from T1 where info in (select info from T2) but it fails if i have more that 5.000 records. Is there another way to do this ?

Performing A Check
I have a table called customer with a field called dateAtAddress. I want to perfrom a check so that when a new record is created the dateAtAddress must be in the past. I have tried the following code when creating the table

dateAtAddress date,
CHECK
dateAtAddress <= DATE_SUB(CURRENT_DATE, INTERVAL 0 DAY);

But it still seems to be letting datesin the future be entered in as valid data in the field.

User Check
I want to add a new user but I donâ€™t know whether a user already exists
How can I check whether a user already exists?
This donâ€™t work
CREATE USER IF NOT EXISTS admin

Mysql: Check
Is there any possibility to check existing of autoextend option
for InnoDB ?
I mean by any sql command and not by searching in my.ini file ?

Syntax Check
Code:

SELECT (((b.close - a.close) / a.close) * 100) FROM `AAH` a, `AAH` b WHERE b.date = '2007-01-03' AND a.date = '2007-01-02'

and said error:

Quote: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'b.close - a.close) / a.close) * 100) FROM `AAH` a, `AAH` b WHERE b.date = '2007-' at line 1
it is supposed to retrieve and calculate the percent change for the closing prices of a symbol on a particular stock market. Not sure what the exact error is.

Date Check Constraint
I'm trying to tack on a check constraint to make sure that when a check-out date is added, to make sure the check-in date is <= the check-out date. A simple inequality throws an error. What would be the correct way to handle this?

Create table maintenance(
mid char(5) primary key not null,
cid char(5) not null references cars(cid),
pid char(5) not null references people(pid),
check_in_date date not null,
check_out_date CHECK (check_in_date<= check_out_date),
milage int not null CHECK(milage>=0),
service_description varchar (255),
UNIQUE(mid)
);

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'CHECK (check_in_date<= check_out_date), milage int not null CHECK(milage>=0), ' at line 6

Check If Column Exists
I want to check if a column exists in a select statement. I've done searches on google and have not found what I need.

If a column exists, include the column in the query, else not. Here's an example of what I might want to do, but it doesn't work:

select cat_title, if(column_exists('subhead')) then subhead from wf_category where cat_id=5

I know I can do a separate select statement to check for this, but I'd rather save the overhead and do it all in one statement.

Check For Duplicate Fields?
I have a product table, alot of the information can be the same for 2 different products but the one thing that absolutely differs them is the style number. Theres alot of products on the site and its hard to keep track of all of them. if there is no duplicates then every single field for the style number should be different. So If there was a duplicate product the style column would be the same in 2 or places. So what I am asking is if there is a way I can pull a field only if there is more than one occurance of it? Kinda like a SELECT DISTINCT in reverse. That way I can find diplicate products and remove them.

Actually an even better thing would be if there was a way I could set the table to reject any inserts if the style umber column is the same as one that already exists....but I dont know if thats possible either.

How Check How Long Did My Select Took ?
I have a client for mysql which give me the time it took to query but now is very doubtful. I have 2 machines on the same network accessing the same database one is showing 360ms and the other is showing 5469ms on the same select? Thus I am very confuse where can I verify which is the exact time ? Thanks.

I Want To Check That A String Is In A Field
I want to select everything where a specific short string, is in the actual field. Eg, if I use a search string of alpine, it will be 'in' the field value Alpine Forests, so I will select the field that contains Alpine Forests.

This is my SQL so far and it doesn't work

SELECT * from packages2_tbl WHERE (INSTR(model, LCASE('Alpine'))) AND product_active = 'yes' ORDER BY model ASC"
Has anyone got any ideas?

Is It Possible To Check For The First Chars In A Db - Column?
Trying to compare the first 4 chars with the first 4 chars in a db column ....

Check Before Insert Query
if (!empty($determin))
{
//do something when its not empty

$query = "SELECT * FROM `JS` WHERE `wrdnprc` LIKE '$mkrs' LIMIT 1";
$good_query=mysql_query($query) or die(mysql_error());

if (mysql_num_rows($good_query) == 1 )

{
echo "record found #2 ";
}
else
{
$query = "INSERT INTO `JS` ( `id` , `wrdprc` , `wrdnprc` , `pgld` ) VALUES ('', '$mkrs', '2', '0') ";
$query=mysql_query($query) or die(mysql_error());

echo "adding record #2 "; }
}
else
{
//its empty... lets whine about it
echo "no ";
}

most of the work is being done, which is good thing BUT the query will INSERT regardless of the if good_query statement.

Check Table For An Entry?

I'm currently working on some rudamentry administration, namely an IP ban list. I want to make it so that if the user trys to ban an IP that is already in the list, the entry will be removed instead. what would be the best way to go about this?