I have this problem.
One table with.
id | routename | usersid |
1 | route 1 | 1,2,3,5 2 |
2 | route 2 | 5,20,15 3 |
4 | route 4 | 10,15,7,5 |
I need, search ej. userid 5 in colum usersid... but I have no idea how to do, because there are multiple rows.
If you cannot change the schema then you will have to use the REGEXP operator to match on a regular expression. For example
where column REGEXP '(^|,)5(,|$)'
This matches the number 5 either at the beginning or end of the field or surrounded by commas (or any combination thereof), to avoid matching other numbers like 15, 55 or 1234567890.
If the table is large this will perform very slowly as it will require a full table scan
You might be looking for FIND_IN_SET().
select * from Table1
WHERE FIND_IN_SET(5,usersid)
SAMPLE FIDDLE
Related
I have a situation in MS Access database that I must prevent duplicate records based on combination of three attributes:
StudentNumber
ColleagueID
TypeOfAttending
So, for one combination (StudentNumber & ColleagueID) I have three types of attending: A, B and C.
Here is an example:
+---------------+-------------+---------------+
| StudentNumber | ColleagueID | AttendingType |
+---------------+-------------+---------------+
| 100 | 10 | A |
| 100 | 10 | B |
| 100 | 10 | C |
| 100 | 11 | A |
| 100 | 11 | B |
| 100 | 11 | C |
| 100 | 11 | C |
+---------------+-------------+---------------+
So last row would not be acceptable.
Does anyone have any idea?
As noted, you could choose all 3 as a PK. Or you can even create a unique index on all 3 columns. These two ideas are thus code free.
Last but least, you could use a Before change macro,and do a search (lookup) in the table to check if the existing record exists. So far, given your information, likely a unique index is the least effort, and does not require you to change the PK to all 3 columns (which as noted is a another solution).
So, you could consider a before change macro. And use this:
Lookup a Record in MyTable
Where Condition = [z].[Field1]=[MyTable].[Field1] And
[z].[Field2]=[MyTable].[Field2] And
[z].[ID]<>[MyTable].[ID]
Alias Z
RaiseError -123
Error Description: There are other rows with this data
So, you can use a data macro, use the before change table macro. Make sure you have the raise error code indented "inside" of the look up code. And note how we use a alias for the look up, since the table name (MyTable) is already in context, and is already the current row of data, so we lookup using "z" as a alias to distinguish between the current row, and that of lookup record.
So, from a learning point of view, the above table macro can be used, but it likely less work and effort to simply setup a uniquie index on all 3 columns.
I have a table that contains a row of phone number prefixes and a row of price for each prefix.
Sample table:
prefix | price
---------------------
| 21366 | 0.15 |
| 2010 | 0.1 |
| 213 | 0.13 |
---------------------
In the website, the user will be asked to insert a phone number (e.g. 21366123456), where i have to search the database table for the most accurate matching.
In this case, even though there is a prefix value of 213 in the table, i will be needing the result of 21366.
How can this be done using a simple MySQL query without looping recursively on the user input value?
Try this:
SELECT prefix, price
FROM mytable
ORDER BY LENGTH('21366123456') - LENGTH(REPLACE('21366123456', prefix, '')) DESC LIMIT 1
Demo here
I'm having a query problem. I use mysql as DB. I want to use a REGEX to match the result I expected and The Table is
table A
----------------------------------
| ID | Description |
----------------------------------
| 1 | new 2 new 2 new 2 new |
| 2 | new 21 new 2 new |
| 3 | new 12th 2 |
| 4 | 2new 2new |
| 5 | new2 new 2new |
The Result I expected
- numeric 2 can only show twice
- character after/before 2 must be varchar (except after whitespace)
Table B
---------------------------------
| ID | Description |
---------------------------------
| 4 | 2new 2new |
| 5 | new2 new 2new |
The Query I've got so far:
SELECT * FROM a WHERE
(description REGEXP '^[^2]*2[^2]*2[^2]*$')
click here for sqlfiddle demo
could anyone help me to solve this?
Use the below regex to get the Description of fourth and fifth ID's.
SELECT * FROM a WHERE
(description REGEXP '^2[^2]*2[^2]*|\w+2[^2]*2[^2]*$')
http://sqlfiddle.com/#!2/1284e/18
Explanation:
Divide the above regex into two like 2[^2]*2[^2]* as one part and \w+2[^2]*2[^2]* as another part. In regex ^ represents the starting point and $ represents the end point.
2[^2]*2[^2]*
2 Matches the number 2.
[^2]* Matches any character not of 2 zero or more times.
2 Matches the number 2.
[^2]* Matches any character not of 2 zero or more times.
This would get you the 4th ID.
| A logical OR operator usually used to combine two regexes which means match either this(before) or that(after).
\w+2[^2]*2[^2]*
\w+2 Matches one or more word characters which should be followed by the number 2. In your example, 5th ID satisfy this regex.
[^2]* Matches any character not of 2 zero or more times.
2 Matches the number 2.
[^2]* Matches any character not of 2 zero or more times.
This would get you the 5th ID.
Hey all, I am looking for a way to query my database table only once in order to add an item and also to check what last item count was so that i can use the next number.
strSQL = "SELECT * FROM productr"
After that code above, i add a few product values to a record like so:
ID | Product | Price | Description | Qty | DateSold | gcCode
--------------------------------------------------------------------------
5 | The Name 1 | 5.22 | Description 1 | 2 | 09/15/10 | na
6 | The Name 2 | 15.55 | Description 2 | 1 | 09/15/10 | 05648755
7 | The Name 3 | 1.10 | Description 3 | 1 | 09/15/10 | na
8 | The Name 4 | 0.24 | Description 4 | 21 | 09/15/10 | 658140
i need to count how many times it sees gcCode <> 'na' so that i can add a 1 so it will be unique. Currently i do not know how to do this without opening another database inside this one and doing something like this:
strSQL2 = "SELECT COUNT(gcCode) as gcCount FROM productr WHERE gcCode <> 'na'
But like i said above, i do not want to have to open another database query just to get a count.
Any help would be great! Thanks! :o)
There's no need to do everything in one query. If you're using InnoDB as a storage engine, you could wrap your COUNT query and your INSERT command in a single transaction to guarantee atomicity.
In addition, you should probably use NULL instead of na for fields with unknown or missing values.
They're two queries; one is a subset of the other which means getting what you want in a single query will be a hack I don't recommend:
SELECT p.*,
(SELECT COUNT(*)
FROM PRODUCTR
WHERE gccode != 'na') AS gcCount
FROM PRODUCTR p
This will return all the rows, as it did previously. But it will include an additional column, repeating the gcCount value for every row returned. It works, but it's redundant data...
I've got a table in MySQL that looks roughly like:
value | count
-------------
Fred | 7
FRED | 1
Roger | 3
roger | 1
That is, it was created with string ops outside of MySQL, so the values are case- and trailing-whitespace-sensitive.
I want it to look like:
value | count
-------------
Fred | 8
Roger | 4
That is, managed by MySQL, with value a primary key. It's not important which one (of "Fred" or "FRED") is kept.
I know how to do this in code. I also know how to generate a list of problem values (with a self-join). But I'd like to come up with a SQL update/delete to migrate my table, and I can't think of anything.
If I knew that no pair of records had variants of one value, with the same count (like ("Fred",4) and ("FRED",4)), then I think I can do it with a self-join to copy the counts, and then an update to remove the zeros. But I have no such guarantee.
Is there something simple I'm missing, or is this one of those cases where you just write a short function outside of the database?
Thanks!
As an example of how to obtain the results you are looking for with a SQL query alone:
SELECT UPPER(value) AS name, SUM(count) AS qty FROM table GROUP BY name;
If you make a new table to hold the correct values, you INSERT the above query to populate the new table as so:
INSERT INTO newtable (SELECT UPPER(value) AS name, SUM(count) AS qty FROM table GROUP BY name);
Strangely, MySQL seems to do this for you. I just tested this in MySQL 5.1.47:
create table c (value varchar(10), count int);
insert into c values ('Fred',7), ('FRED',1), ('Roger',3), ('roger',1);
select * from c;
+-------+-------+
| value | count |
+-------+-------+
| Fred | 7 |
| FRED | 1 |
| Roger | 3 |
| roger | 1 |
+-------+-------+
select value, sum(count) from c group by value;
+-------+------------+
| value | sum(count) |
+-------+------------+
| Fred | 8 |
| Roger | 4 |
+-------+------------+
I was surprised to see MySQL transform the strings like that, and I'm not sure I can explain why it did that. I was expecting to have to get four distinct rows, and to have to use some string functions to map the values to a canonical form.