I am creating a table with several columns in sql:
CREATE TABLE.....
and one of them is going to have values like this: 675763582022462206:57. As you see it has : in it. So what is a type of it? Is it UInt16 or String?
It must be varchar or nvarchar in this case. The database doesn't recognize ":" as a part of a number, unless you say to Windows in advanced region settings that this is your decimal point. If you can store 57 (after ":") in a different column, then you can save the number before ":" as a bigint if you wish
This value can't be stored in a numeric type due to the colon (:), so you'll have to use one of the character types - i.e., a sufficiently long char or varchar.
Related
How to find the count of character mismatch between two values in a SQL Server stored procedure? It's not about the length difference.
For example, there are two values,
Reference value ='Visual'
Test value ='Visvolc'
Mismatch = 3 chars (4th, 5th and 7th position)
There is 3 character mismatch based on the position. please help.
Sounds like what you are looking for is “edit distance”, a number of add/remove/replace operation to convert one string into another. Check this post: Levenshtein distance in T-SQL
I need store exactly numeric data in database.
Let say have to save 123.200 or 123.1 exactly into database.
But result will come up 123.20 or 123.10 in database if column type set to decimal with fixed 2 digit.
What I can do if I just want 123.200 or 132.1 shown on database/report?
No need system auto convert to any other decimal.
You can store the value "as is" in the varchar type.
The problem with this approach is that database would allow to store any string there, even if it is not a number, say 10abc.xyz23
If you need to know how to present the number to the user, you need to store this information somehow. Since, each number in the column may be formatted differently, you need to store this formatting information for each row.
I'd store it as decimal type with large enough scale and precision to cover all possible ranges of your data and in addition to that have extra column DecimalPlaces, which would contain the number of decimal places your reporting engine should use when displaying the value.
If you must do this, then as others have suggested, you'll need to use a character data type to store it. I'd also add a computed column that makes the numeric value readily available also:
create table T (
Val varchar(39) not null,
Val_numeric as CONVERT(decimal(38,10),Val) persisted
)
go
insert into T(Val) values
('123.200'),
('123.1')
select * from T
Results:
Val Val_numeric
--------------------------------------- ---------------------------------------
123.200 123.2000000000
123.1 123.1000000000
When you need the "user entered" value, you use Val. When you need the real value, you use Val_Numeric. This also has the advantage that (without a complex check constraint), you cannot enter any invalid values into the Val column. E.g.:
insert into T(Val) values ('1.2.3')
Produces the error:
Msg 8114, Level 16, State 5, Line 12
Error converting data type varchar to numeric.
I have a nvarchar column in one of my tables that I have imported from Access. I am trying to change to an int. To move to a new table.
The original query:
insert into members_exams_answer
select
ua.members_exams_id, ua.exams_questions_id,
ua.members_exams_answers_value, ua.members_exams_answers_timestamp
from
members_exams as me
full join
UserAnswers1 as ua on me.members_exams_username = ua.members_exams_id
full join
exams_questions as eq on eq.exams_questions_id = ua.exams_questions_id
This throws an error:
Conversion failed when converting the nvarchar value 'AAAR78509883' to data type int.
I have tired:
select convert (int, UserAnswers1.members_exams_id)
from UserAnswers1
and
select cast(members_exams_id as integer) int_members_exams_id
from UserAnswers1
and
select cast (members_exams_id as int)
from UserAnswers1
All result in the same error
Conversion failed when converting the nvarchar value 'AAAR78509883' to data type int.
Clearly you are trying to convert data that is alphanumeric to an int and that cannot be done.
Looking at your data why are you insisting on converting it to an int when it cannot be an int? Why not just process it as an nvarchar?
Your problem could be systemic where all data has a leading alpha characters that you need to strip out (and hopefully the same number of alpha characters)
In that case use a substring to strip off the alphas (this assumes the name number of alphabetic characters in each record). Or use a varchar or nvarchar field instead of an int. If the number of leading characters varies or if they can be leading or trailing or some other combination, it will much more complex to fix than we can probably describe on the Internet.
The other possibility is that you simply have some bad data. In which case identify the records which are not numeric and fix them or null the value out if they cannot be fixed. This happens frequently when you have stored the data in an incorrect datatype.
I import Excel files via SSIS to SQL-Server. I have a temp table to get everything in nvarchar. For four columns I then cast the string to money type and put in my target table.
In my temp table one of those four columns let me call it X has a comma as the delimiter the rest has a dot. Don't ask me why, I have everything in my SSIS set the same.
In my Excel the delimiter is a comma as well.
So now in my target table I have everything in comma values but the X column now moves the comma two places to the right and looks like this:
537013,00 instead of 5370,13 which was the original cell value in the temp and excel column.
I was thinking this is a culture setup problem but then again it should or shouldn't work on all of these columns.
a) Why do I receive dot values in my temp table when my Excel displays comma?
b) how can I fix this? Can I replace the "," in the temp table with a dot?
UPDATE
I think I found the reason but not the solution:
In this X column in excel the first three cells are empty - the other three columns all start with 0. If I fill these three cells of X with 0s then I also get the dot in my temp table and the right value in my target table. But of course I have to use the Excel file as is.
Any ideas on that?
Try the code below. It checks whether the string value being converted to money is of numeric data type. If the string value is of numeric data type, then convert it to money data type, otherwise, return a NULL value. And it also replaces the decimal symbol and the digit grouping symbol of the string value to match the expected decimal symbol and digit grouping symbol of SQL Server.
DECLARE #MoneyString VARCHAR(20)
SET #MoneyString = '$ 1.000,00'
SET #MoneyString = REPLACE(REPLACE(#MoneyString, '.', ''), ',', '.')
SELECT CAST(CASE WHEN ISNUMERIC(#MoneyString) = 1
THEN #MoneyString
ELSE NULL END AS MONEY)
As for the reason why you get comma instead dot I have no clue. My first guess would be cultural settings but you already checked that. What about googling, did you get some results?
First the "separator" in SQL is the decimal point: its only excel that is using the comma. You can change the formatting in excel: you should format the excel column as money and specify a decimal point as the separator. Then in the SSIS import wizard split out the transformation of the column so it imports to a money data type. Its a culture thing, but delimiter tends to be used in the context of signifying the end of one column and the start of the next (as in csv)
HTH
Well thats a longstanding problem with excel. It uses the first 30 or so rows to infer data type. It can lead to endless issues. I think your solution has to be to process everything as a string in the way Yaroslav suggested, or supply an excel template to have data predefined and formatted data type columns, which then have the values inserted. Its a pita.
Just to clarify, by specifying something like VARCHAR(45) means it can take up to max 45 characters? I remember I heard from someone a few years ago that the number in the parenthesis doesn't refer to the number of characters, then the person tried to explain to me something quite complicated which I don't understand and forgot already.
And what is the difference between CHAR and VARCHAR? I did search around a bit and see that CHAR gives you the max of the size of the column and it is better to use it if your data has a fixed size and use VARCHAR if your data size varies.
But if it gives you the max of the size of the column of all the data of this column, isn't it better to use it when your data size varies? Especially if you don't know how big your data size is going to be. VARCHAR needs to specify the size (CHAR don't really need right?), isn't it more troublesome?
You also have to specify the size with CHAR. With CHAR, column values are padded with spaces to fill the size you specified, whereas with VARCHAR, only the actual value you specified is stored.
For example:
CREATE TABLE test (
char_value CHAR(10),
varchar_value VARCHAR(10)
);
INSERT INTO test VALUES ('a', 'b');
SELECT * FROM test;
The above will select "a " for char_value and "b" for varchar_value
If all your values are about the same size, the CHAR is possibly a better choice because it will often require less storage space than VARCHAR. This is because VARCHAR stores both the length of the value and the value itself, whereas CHAR can just store the (fixed-size) value.
The MySQL documentation gives a good explanation of the storage requirements of the various data types.
In particular, for a string of length L, a CHAR(M) datatype will take up (M x c) bytes (where c is the number of bytes required to store a character... this depends on the character set in use).
A VARCHAR(M) will take up (L + 1) or (L + 2) depending on whether M is <=255 or >255.
So, it really depends on how long you expect your strings to be, what the variation in length will be.
NB: The documetation doesn't discuss the impact of character sets on the storage requirements of a VARCHAR type. I've tried to quote it accurately, but my guess is that you would need to multiply the string length by the character byte-width as well to get the storage requirement.
The complicated stuff you don't remember is that the 45 refer to bytes, not chars. It's not the same if you are using a multibyte character encoding. In Oracle you can specify bytes or chars explicitly.
varchar2(45 BYTE)
or
varchar2(45 CHAR)
See Difference between BYTE and CHAR in column datatypes
char and varchar actually becomes irrelevant if you have just 1 variable length field in your table, like a varchar or text. Mysql will automatically change all char to varchar.
The fixed length/size record can give you extra performance, but you can't use any variable length field types. The reason is that it will be quicker and easier for mysql to find the next record.
For example, if you do a SELECT * FROM table LIMIT 10, mysql has to scan the table file for the tenth record. This means finding the end of each record until you find the end of the 10th record. But if your table has fixed length/size records, mysql just needs to know the record size and then skip 10 x #bytes.
If you know a column will contain a small, fixed number of chars use a CHAR, otherwise use a varchar. A CHAR column is padded to the max length.
VARCHAR has a small overhead (4-8 bytes depending on RDBMS), but only uses the overhead + the actual number of chars stored.
For the values you know they are going to be constant, for example for Phone Numbers, Zip Codes etc., It is optimal to use "char" for sure.