I have a reshift table, which has a decimal column of (38, 29), but the original data's maximum Integer part is 6 and scale is 12 i.e Decimal (18,12). But the table is created using the max precision and scale. So all the data in that has 0's at the end of the scale part as padding.
For Example:
12345.123456789112300000000000000000000
All the data in the table is like the above example.
Now I'm retrieving the data from the table using the below query.
select cast(column as decimal(30,6)) from table;
The output I'm getting is
12345.123456
But when I try the below query
select cast(12345.123456789112300000000000000000000 as decimal(30,6)) from table;
The output I'm getting is
12345.123457
I want to know why this is happening. when I cast the column in the table, it is not rounding off to its highest value, it is just truncating.
But when I try with the decimal itself it is truncating and it is rounding off.
I also want to how to achieve the second query's result in the table itself.
So this comes down to when is a cast not a cast. If I cast and integer to an int it does nothing. Casting a varchar to a shorter varchar is nearly as simple as long as the data fits. Casting a decimal to a lower scale decimal is also a simplistic operation as it is not changing the data type, just some attribute of it (scale). What you desire is that Redshift implicitly ROUNDS the values when you make this conversion and it is not. (I'll let the database philosophers debate if this is a bug or not.)
Here's a simple example to highlight this:
drop table if exists goo;
create table goo (rownum int, num decimal(30,6));
insert into goo select 1, 12345.123456789112300000000000000000000::text;
insert into goo select 2, 12345.123456789112300000000000000000000::decimal(38,29);
insert into goo select 3, 12345.123456789112300000000000000000000::double;
select rownum, num::text from goo;
In all 3 of these examples there is an implicit cast to the data type of the column 'num' in the table. However you can see that what is getting into the table is different. Lots of experiments can be set up like this. (Note that I'm casting the result to text to avoid any bench precision changes.)
The answer in your case is to explicitly ROUND() the value.
Related
I'm getting a query from a column float (with no precision) and inserting it in another table and comumn float (with no precision as well) but I'm getting this error:
Error (265) Insufficient result space for explicit conversion of FLOAT value '3.8833137793643' to a VARCHAR field.
The query:
INSERT INTO TableA
SELECT DISTINCT max(price_1) AS PriceValue
FROM TableB
This does may or may not answer your question. But the query should be written as:
INSERT INTO TableA (<column name>)
SELECT MAX(price_1) AS PriceValue
FROM TableB;
Notes:
An aggregation query with no GROUP BY returns exactly one row. SELECT DISTINCT is not necessary.
You should include the columns being inserted.
Your problem is clearly that the column is not wide enough. If you have defined the table as:
create table tableA (
col varchar
);
Then you have not specified a length and are depending on the default in the database. Do you even know what the default is? In this case, it is 1. And that is not long enough for your value. You just need to provide a long-enough length:
create table tableA (
col varchar(255)
);
All that said. I strongly discourage you from storing number values as strings. That is likely to create problems now and in the future. Use the appropriate types for your data.
I have to check for wrong values using regexp_like expression. As far as I am concern I can do this only on strings and my data is saved in database as double.
I tried to cast it
SELECT column
FROM table
WHERE NOT REGEXP_LIKE(CAST(DECFLOAT(column) as VARCHAR(25)), '(\d{6}\.?\d{2})|(\d{7}\.?\d)')
Unfortunately values like 1234567.0 are converted into 1234567 and as a result this query is returning it as a mistake.
The other solution like
SELECT column
FROM table
WHERE NOT REGEXP_LIKE(CAST(CAST(column AS DECIMAL(8,1)) AS VARCHAR(25)), '(\d{6}\.?\d{2})|(\d{7}\.?\d)')
leads to a problem where values like 134567.89 are converted to 1234567.8 and are not returned by the query as an incorrect value.
Is there a way to cast it to varchar without giving it a range?
For 1st Query, Don't Convert column to DECFLOAT.
SELECT column
FROM table
WHERE NOT REGEXP_LIKE(CAST(CAST(column as DECIMAL(8,2)) as VARCHAR(25)), '(\d{6}\.?\d{2})|(\d{7}\.?\d)')
For 2nd Query, Increase the fraction part of the DECIMAL(8,1) to DECIMAL(8,2) to get the desired Result.
SELECT column
FROM tabel
WHERE NOT REGEXP_LIKE(CAST(CAST(column AS DECIMAL(8,2)) AS VARCHAR(25)), '(\d{6}\.?\d{2})|(\d{7}\.?\d)')
I'm developing a database with SQL Server 2012 SP2.
I have a table with a NVARCHAR(20) column, and it will have numbers: "000001", "000002", etc.
I need to get the greatest value in that column and convert it to int. How can I do it?
I have found that I can convert a nvarchar to int with this sql sentence:
SELECT CAST(YourVarcharCol AS INT) FROM Table
But I don't know how can I get the max value in that column because the numbers are nvarchar.
UPDATE:
By the way, this column is NVARCHAR because I need to store text on it. I'm testing my solution and I need to store ONLY numbers to test it.
If your numbers are padded like in the example given and all have the same width, you can just sort them alphanumerically and then cast the max-value to INT or BIGINT (depending on your numbers range).
If there are very many rows it was much faster, especially if there is an index on this column...
Something like
SELECT TOP 1 * FROM YourTable
ORDER BY NumberColumn DESC
or, if you need the max-value only:
SELECT MAX(NumberColumn) FROM YourTable
If you have to deal with negative numbers or differently padded numbers you have to cast them first
SELECT TOP 1 * FROM YourTable
ORDER BY CAST(NumberColumn AS INT) DESC
or
SELECT MAX(CAST(NumberColumn AS INT)) FROM YourTable
Please note:
If you've got very many rows, the second might get rather slow. Read about sargable
If your NumberColumn might include invalid values, you have to check, Read about ISNUMERIC().
The best solution - in any case - was to use an indexed numeric column to store these values
Try this one...
I think MAX is enough.
SELECT max(CAST(YourVarcharCol AS INT)) FROM Table
Try this
SELECT MAX(t.Y) from (SELECT CAST(YourVarcharCol AS INT) as Y FROM Table) t
You should try this on finding the highest value:
SELECT MAX(CAST(YourVarcharCol AS INT)) AS FROM Table
If all the data follow the same padding and formatting pattern, a simple max(col) would do.
However, if not, you have to cast the values to int first. Searching on a columns cast to some other datatype will not use an index, if there's any, but will scan the whole table instead. It may or may not be OK for you, depending on requirements and number of rows in the table. If performance is what you need, then create a calculated column as try_cast( col as int), and create an index on it.
Note that you should not use cast, but try_cast instead, to guard against values that can't be cast (if you use a datatype to store something which is essencially of another datatype, it always opens up a possibility for errors).
Of couse, if you can change the original column's type to int, it would be the best.
This will return max int value
SELECT MAX(IIF(ISNUMERIC(YourVarcharCol) = 1, YourVarcharCol, '0') * 1) FROM Table
You can use like this
select max(cast(ColumnName AS INT ))from TableName
I got a sql server error and not sure how to fix it.I got a column 'NAME' in a view 'Products' with a type of nvarchar(30), the query is generated dynamically in code so cannot quite change it.
I got the 'Arithmetic overflow error converting nvarchar to data type numeric.' for the following query:
select * FROM Products WHERE NAME=12.0
however the following query works fine:
select * FROM Products WHERE NAME=112.0
I am quite confused by the error, I know I should put quotes around the number but just want know why the second query works and is there any settings could make the first query work?
update: also
select * FROM Products WHERE NAME=cast('12.0' as decimal(4,2))
doesn't work, but
select * FROM Products WHERE NAME=cast('12.0' as decimal(5,2))
works, any particular reasons?
Many thanks!
SQL Server is trying to convert the values in your table to match the perceived data type of the value coded into your WHERE clause. If you have data values with more numbers (e.g., DECIMAL(5,2)) and you try to convert them to match a value with fewer (e.g., DECIMAL(3,1)), then you will have an overflow.
Consider the following SQL, which will throw an error:
DECLARE #Products TABLE (NAME NVARCHAR(30))
INSERT INTO #Products VALUES ('123.45')
INSERT INTO #Products VALUES ('12.0')
SELECT *
FROM #Products
WHERE NAME = 12.0
Now try this, which will work:
DECLARE #Products TABLE (NAME NVARCHAR(30))
INSERT INTO #Products VALUES ('123.45')
INSERT INTO #Products VALUES ('12.0')
SELECT *
FROM #Products
WHERE NAME = CAST(12.0 AS DECIMAL(5,2))
The difference between these is that SQL Server now accounts for cases where the table contains a number with a higher precision and/or scale than the one specified in the WHERE clause.
EDIT: further reading. Books Online states in the data type definition for DECIMAL and NUMERIC that:
In Transact-SQL statements, a constant with a decimal point is
automatically converted into a numeric data value, using the minimum
precision and scale necessary. For example, the constant 12.345 is
converted into a numeric value with a precision of 5 and a scale of 3.
Therefore, when you issue a query with the constant '12.0', it is being converted to the data type NUMERIC(3,1) and then trying to convert the NVARCHAR value to match.
I have a column in a table with a varchar datatype. It has 15 digits after the decimal point. Now I am having a hard time converting it to a numeric format.. float, double etc.
Does anyone have any suggestions?
Example :
Table1
Column1
-------------------
-28.851540616246499
-22.857142857142858
-26.923076923076923
76.19047619047619
I tried using the following statements and it doesn't seem to work :
update table1
set Column1 = Convert(float,column1)..
Any suggestions ?
You can use the decimal data type and specify the precision to state how many digits are after the decimal point. So you could use decimal(28,20) for example, which would hold 28 digits with 20 of them after the decimal point.
Here's a SQL Fiddle, showing your data in decimal format.
Fiddle sample:
create table Table1(MyValues varchar(100))
insert into Table1(MyValues)
values
('-28.851540616246499'),
('-22.857142857142858'),
('-26.923076923076923'),
('76.19047619047619')
So the values are held as varchar in this table, but you can cast it to decimal as long as they are all valid values, like so:
select cast(MyValues as decimal(28,20)) as DecimalValues
from table1
Your Sample
Looking at your sample update statement, you wouldn't be able to convert the values from varchar to a numeric type and insert them back in to the same column, as the column is of type varchar. You would be better off adding a new column with a numeric data type and updating that.
So if you had 2 columns:
create table Table1(MyValues varchar(100), DecimalValues decimal(28,20))
You could do the below to update the numeric column with the nvarchar values that have been cast to decimal:
update Table1
set DecimalValues = cast(MyValues as decimal(28,20))
I think you're trying to actually change the data type of that column?
If that is the case you want to ALTER the table and change the column type over to float, like so:
alter table table1
alter column column1 float
See fiddle: http://sqlfiddle.com/#!6/637e6/1/0
You would use CONVERT if you're changing the text values to numbers for temporary use within a query (not to actually permanently change the data).