I want to delete a certain string in a cell in MS Access, whether in a column or in the whole table. I know that I can do this using plain old Find and Replace but in this case it is not economical for my thousand-row table.
For example,
remove all Unknown values from all columns.
remove the string "dollars" from the values in column price ie. if the cell contains "34 dollars", it will just be "34".
Can this be done in SQL and how?
Assuming your query will run within an Access session, the second goal is easy. You can Replace dollars with a zero-length string.
UPDATE YourTable
SET price = Replace(price, 'dollars', '');
You could use the same strategy for the first goal, but may decide it makes more sense to examine the datatypes of the table's fields and only UPDATE those which are text or memo.
Related
I am new to PostgreSQL and am attempting to create a query that will clean up certain columns within a table. By "clean up" I mean delete all characters before or after a certain symbol.
I have one column called "Campaign" within a table called "Adwords".The column has this string/structure within all rows, DE-SRC-Brand. The only place that I would like to keep in this column would be where Brand currently is. I had previously done this manually through excel by doing a simple search and replace with "*-" as the searching criteria.
How would this formula translate to PostgreSQL? How would it then also change if I would like to delete characters in front of a certain designated symbol. Please let me know if anything is unclear as I am still new to this program.
If you want to extract the brand, you can use substring() with a pattern:
select substring(campaign from '%-%-#"%#"' for '#') as brand
from adwords;
You can incorporate this into an update:
update adwords
set campaign = substring(campaign from '%-%-#"%#"' for '#')
where campaign like '%-%-%';
I have problems with my records within my database, so I have a template with about 260,000 records and for each record they have 3 identification columns to determine what time period the record is from and location: one for year, one for month, and one for region. Then the information for identifying the specific item is TagName, and Description. The Problem I am having is when someone entered data into this database they entered different description for the same device, I know this because the tag name is the same. Can I write code that will go through the data base find the items with the same tag name and use one of the descriptions to replace the ones that are different to have a more uniform database. Also some devices do not have tag names so we would want to avoid the "" Case.
Also moving forward into the future I have added more columns to the database to allow for more information to be retrieved, is there a way that I can back fill the data to older records once I know that they have the same tag name and Description once the database is cleaned up? Thanks in advance for the information it is much appreciated.
I assume that this will have to be done with VBA of some sort to modify records by looking for the first record with that description and using a variable to assign that description to all the other items with the same tag name? I just am not sure of the correct VBA syntax to go about this. I assume a similar method would be used for the backfilling process?
Your question is rather broad and multifaceted, so I'll answer key parts in steps:
The Problem I am having is when someone entered data into this
database they entered different description for the same device, I
know this because the tag name is the same.
While you could fix up those inconsistencies easily enough with a bit of SQL code, it would be better to avoid those inconsistencies being possible in the first place:
Create a new table, let's call it 'Tags', with TagName and TagDescription fields, and with TagName set as the primary key. Ensure both fields have their Required setting to True and Allow Zero Length to False.
Populate this new table with all possible tags - you can do this with a one-off 'append query' in Access jargon (INSERT INTO statement in SQL).
Delete the tag description column from the main table.
Go into the Relationships view and add a one-to-many relation between the two tables, linking the TagName field in the main table to the TagName field in the Tags table.
As required, create a query that aggregates data from the two tables.
Also some devices do not have tag names so we would want to avoid the
"" Case.
In Access, the concept of an empty string ("") is different from the concept of a true blank or 'null'. As such, it would be a good idea to replace all empty strings (if there are any) with nulls -
UPDATE MyTable SET TagName = Null WHERE TagName = '';
You can then set the TagName field's Allow Zero Length property to False in the table designer.
Also moving forward into the future I have added more columns to the
database to allow for more information to be retrieved
Think less in terms of more columns than more tables.
I assume that this will have to be done with VBA of some sort to modify records
Either VBA, SQL, or the Access query designers (which create SQL code behind the scenes). In terms of being able to crunch through data the quickest, SQL is best, though pure VBA (and in particular, using the DAO object library) can be easier to understand and follow.
We are using a database where the front end software has allowed the input of invalid characters. (I have no control or re-writing of the software.)
The types of characters are carriage returns, line breaks, �, ¶, basically anything that is not 0-9, a-z or standard punctuation causes us issues with the database and how we use the data.
I'm looking for a way to scan the entire database to identify these invalid codes and either display them as results or strip them out?
I had been looking at This site wondering if there was a way of searching for a certain range? But I might be barking up the wrong tree.
I'm fairly new to SQL so be gentle with me, thanks.
The only way I could think to do this would be to write a stored procedure which uses system tables to get a list of all fields in the database/schema in question. Have it exclude system tables (or only include those that are user defined) then dynamically write out SQL update statements based on the columns/tables found in the system table inquiries. Using regular expressions or character removal like in this article
The system tables in question are:
SELECT
table_name,column_name
FROM
information_schema.columns
Psudo code would be:
Get list of tables we want to do this for
For each table in list
get list of columns for table that have string data.
For each column in table
generate update statement to strip unwanted characters
--Consider writing out table, column key, before after values to history table. incase this
has to be undone.
--Consider counter so I have an idea of what was updated
execute updatestatement
next column
next table
write out counter
Since you say
the data then moves to a second program that cannot handle these
characters and this causes the process to fail.
I'm wondering if you can leave the unreadable data where it is and create a new column for changed data that's only populated if/when the 2nd process fails. You'll still have to test every character of the data in the failed cell, but you wouldn't have to test every character of every row. After you determine the updated text to process, you can call the 2nd process again with the updated value.
In my Access database, I have a table called customers. In this table I have a column called DateEntered. The data type for the field is short text.
The values in this column are not coherent - they come in several variations:
MM-DD-YYYY,
MMDDYYYY and
MM/DD/YYYY.
There doesn't seem to be any standard set.
My goal is to select all customers from 2012. I tried
select *
from customers
where DateEntered <('%2013') AND >('%2012');
but it comes up blank when I run it.
Can anyone point out what I'm failing to do correctly & more importantly explain why exactly this query doesn't work in Access? From my understanding of SQL (not very advanced) this should work.
Another variant)
select * from customers where RIGHT(DateEntered, 4) = '2012'
If you have control over the database and application code, the best way to handle this is to use an actual Date field instead of text in the table.
One way to handle this would be to add a new field to the table, write a query or two to correctly convert the text values to actual date values, and populate the new field.
At this point, you would then need to hunt down the application code the refers to this field in any way and adjust to treat the field as a date, not text. This includes your insert and update statements, report code, etc.
Finally, as a last step, I would rename the original text field (or remove it altogether) and rename the new date field to the original field name.
Once you fix the problem, querying against the field will be a piece of cake.
Alternatively, if you can't alter the table and source code, you can use the date conversion function CDATE() to convert the text value to an actual date. Note that you may need to guard against non-date entries (NULL or empty string values, as well as other text values that aren't really dates in the first place). The IsDate() function can be your friend here.
If you have the time and patience, fixing the data and code is the better approach to take, but sometimes this isn't always feasible.
Why don't you use LIKE operators (they're appropriate when you have a pattern using % and _):
select * from customers where DateEntered like '%2013' or DateEntered like '%2012'
Fellow overflowers,
I am working with a database to sort several other databases and change some values so my scada application can use the values in the database.
Now I have encountered the following problem:
I have a column called "Name" and in this column are string values like this one:
S1\SVS_AK\STS\Status[7]
From this string I'd like to cut (or copy, doesn't really make a difference eitherway) the "[7]" part and paste this behind whatever I have in a different column.
So for example:
I have a column "Address" and a column "Name"
I want to take the [7] from the Name Column and paste that behind the already existing string "DB32,7.3" wich exists in the column Address
How can I possibly do this? Preferably with a query
Thanks in advance!
How about:
UPDATE ATable SET AField2 = Mid(AField,instr(AField,"[")) & AField2
You might like to add
WHERE AField Like "*[[]*"
[ is a special character, so it need to be bracketed for the Like statement, as illustrated.