I am attempting to find the first numeric character in an ID composed of a client segment identifier (ABC_), a geographic identifier (UK) and a number (1234567).
The ID will without exception follow this logic:
ABC_UK1234567
From this, I need to extract the number only (the location identifier will have different lengths, as it could be ABC_UK, ABC_CHR or ABC_I etc., as will the number itself).
I was attempting to use Right(ID, InStr(1,ID,“{1-9}“)) but am unsure how to specify that I am looking for ANY number (maybe a composite of OR statements in the InStr function).
Thank you for any help at all.
You can use this fancy expression in your query, where "1" will preserve a trailing zero:
StrReverse(Mid(CStr(Val("1" & StrReverse([ID]))),2)) As Code
Related
I have a column of strings that have an '&' at the beginning and end of each one that I need to remove for a Crystal report I'm creating. I'm writing the SQL code outside of Crystal I am using Intersystems Cache SQL. Below is an example:
&This& This
&is& is
&What& what
&it& I
&looks& need
&like& it
&now& to
look
like
Any suggestions would be greatly appreciated!!!
Assuming the ampersands are always positioned as both the leading and trailing characters, here's at least maybe a start. Use a combination of SUBSTR (or SUBSTRING, if using stream data) and LENGTH, like so:
SELECT SUBSTR((SELECT column FROM table), 2, LENGTH(SELECT column FROM table) - 2)
This should return a substring that starts counting at the 2nd character [of the original string, given by the first sub-expression/argument to SUBSTR], counting up for the total number of characters [of the original string] less 2 (i.e. less the two ampersands).
If you need to including trailing blanks and/or the string termination character, you may need to use a different variation of the LENGTH function. See resources for details on these functions and their variants:
https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_substr
https://cedocs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_length
Here's a Crystal formula that does the same:
ExtractString({YourData},"&","&")
I have a table with a state column. Inside the state column I have a value like TX` I want to replace that ending character to make the State read TX. How would I do that please give examples
You already have answers for replacing the quote, but I wanted to provide methods for avoiding this problem in the first place.
As noted in #SeanLange's answer, you can use define your State field as a CHAR(2) , so you know that you'll never have a dummy character following a valid state code. You could also handle this in your client code, sanitizing the input before even sending to the database.
One could argue that it would even be a good idea to define a lookup table with a foreign key constraint, so users could only input valid values. You could also use this lookup table client-side (e.g. to provide a list of states).
Of course, you also have to consider internationalization: What about when/if you need to store locations outside of the United States, that may have > 2 characters?
You can escape a single quote by doubling it and including it in quotes. So:
select replace(state, '''', ''')
Of course, if the problem is just a bad third character, then LEFT(state, 2) might do the trick as well.
As a Sean Lang's comment said, you can do this in many different ways. For simplicity, you can just use LEFT(string, #) function for the whole typecasting as long as your raw values are all in the TX` format (**two letter abbrev and one ` , so three characters total for every value in that field.
If that is the case then just do:
SELECT CAST(LEFT(t.state_column, 2) As Varchar(2)) As state,
t.column_2,
t.column_3
/* and so on for all the columns you want */
FROM table t;
--
Further Reference:
- https://w3resource.com/PostgreSQL/left-function.php
I am learning basics of SQL through W3School and during understanding basics of wildcards I went through the following query:
--Finds any values that start with "a" and are at least 3 characters in length
WHERE CustomerName LIKE 'a_%_%'
as per the example following query will search the table where CustomerName column start with 'a' and have at least 3 characters in length.
However, I try the following query also:
WHERE CustomerName LIKE 'a__%'
The above query also gives me the exact same result.
I want to know whether there is any difference in both queries? Does the second query produce a different output in some specific scenario? If yes what will be that scenario?
Both start with A, and end with %. In the middle part, the first says "one char, then between zero and many chars, then one char", while the second one says "one char, then one char".
Considering that the part that comes after them (the final part) is %, which means "between zero and many chars", I can only see both clauses as identical, as they both essentially just want a string starting with A then at least two following characters. Perhaps if there were at least some limitations on what characters were allowed by the _, then maybe they could have been different.
If I had to choose, I'd go with the second one for being more intuitive. After all, many other masks (e.g. a%%%%%%_%%_%%%%%) will yield the same effect, but why the weird complexity?
For Like operator a single underscore "_" means, any single character, so if you put One underscore like
ColumnName LIKE 'a_%'
you basically saying you need a string where first letter is 'a' then followed by another single character and then followed by anything or nothing.
ColumnName LIKE 'a__%' OR ColumnName LIKE 'a_%_%'
Both expressions mean first letter 'a' then followed by two characters and then followed by anything or nothing. Or in simple English any string with 3 or more character starting with a.
I tried to create table named 15909434_user with syntax like below:
CREATE TABLE 15909434_user ( ... )
It would produced error of course. Then, after I tried to have a bit research with google, I found a good article here that describe:
When you create an object in PostgreSQL, you give that object a name. Every table has a name, every column has a name, and so on. PostgreSQL uses a single data type to define all object names: the name type.
A value of type name is a string of 63 or fewer characters. A name must start with a letter or an underscore; the rest of the string can contain letters, digits, and underscores.
...
If you find that you need to create an object that does not meet these rules, you can enclose the name in double quotes. Wrapping a name in quotes creates a quoted identifier. For example, you could create a table whose name is "3.14159"—the double quotes are required, but are not actually a part of the name (that is, they are not stored and do not count against the 63-character limit). ...
Okay, now I know how to solve this by use this syntax (putting double quote on table name):
CREATE TABLE "15909434_user" ( ... )
You can create table or column name such as "15909434_user" and also user_15909434, but cannot create table or column name begin with numeric without use of double quotes.
So then, I am curious about the reason behind that (except it is a convention). Why this convention applied? Is it to avoid something like syntax limitation or other reason?
Thanks in advance for your attention!
It comes from the original sql standards, which through several layers of indirection eventually get to an identifier start block, which is one of several things, but primarily it is "a simple latin letter". There are other things too that can be used, but if you want to see all the details, go to http://en.wikipedia.org/wiki/SQL-92 and follow the links to the actual standard ( page 85 )
Having non numeric identifier introducers makes writing a parser to decode sql for execution easier and quicker, but a quoted form is fine too.
Edit: Why is it easier for the parser?
The problem for a parser is more in the SELECT-list clause than the FROM clause. The select-list is the list of expressions that are selected from the tables, and this is very flexible, allowing simple column names and numeric expressions. Consider the following:
SELECT 2e2 + 3.4 FROM ...
If table names, and column names could start with numerics, is 2e2 a column name or a valid number (e format is typically permitted in numeric literals) and is 3.4 the table "3" and column "4" or is it the numeric value 3.4 ?
Having the rule that identifiers start with simple latin letters (and some other specific things) means that a parser that sees 2e2 can quickly discern this will be a numeric expression, same deal with 3.4
While it would be possible to devise a scheme to allow numeric leading characters, this might lead to even more obscure rules (opinion), so this rule is a nice solution. If you allowed digits first, then it would always need quoting, which is arguably not as 'clean'.
Disclaimer, I've simplified the above slightly, ignoring corelation names to keep it short. I'm not totally familiar with postgres, but have double checked the above answer against Oracle RDB documentation and sql spec
I'd imagine it's to do with the grammar.
SELECT 24*DAY_NUMBER as X from MY_TABLE
is fine, but ambiguous if 24 was allowed as a column name.
Adding quotes means you're explicitly referring to an identifier not a constant. So in order to use it, you'd always have to escape it anyway.
Guys in a few days I have an exam (midterm), so I am trying to execute every possible test which could be in midterm, suppose that we have employees table where phone number is given in this form abc.edf.ghi (all these are numbers not strings), how could I list these employees who's phone number contains edf? I dont think that we can use substring function because it is number, am I correct? Also I can't execute division by sum number like in c++(division by 100,mod 100 and so on,)so please help me, sorry if my question is too much nonsense. I need just for practice.
Oracle says substr is for string only, but you can use substr for columns that are defined as NUMBER datatype,too.
(Assumed that the format of PHONENUMBERCOLUMN is abc.edf.ghi)
select * from YOURTABLE where substr(PHONENUMBERCOLUMN,5,3)='edf'
NOTE: It should be 'edf', not edf, if the datatype is other than NUMBER. Always use single quotation marks to be on the safe side, whether the datatype of the column is number or string (char,varchar,varchar2 etc.)
Don't make a mistake of thinking that phone number is a number. Phone number is a string which usually consists mainly of digits.
Imagine a phone number beginning with some zeros. If you'd store it as a number they will be truncated while they might be important and might make a difference. Storing it as a string makes it secure.
Additionally, storing it as a string enables you to use SUBSTR and other functions named similarly and doing more or less the same thing, which should solve your problem.
In MySQL you can try the SUBSTRING() function. If the phone number is in the format you show it has to be a varchar not a INT.
For Oracle use substr()