I want to know that in redshift maximum precision for decimal is 38, If i use decimal(38,20) will it work?? what are all the limitations using decimal?
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I am confused about the real data type in PostgreSQL:
CREATE TABLE number_data_types (
numeric_column numeric(20,5),
real_column real,
double_column double precision
);
INSERT INTO number_data_types
VALUES (.7, .7, .7),
(2.13579, 2.13579, 2.13579),
(2.1357987654, 2.1357987654, 2.1357987654)
);
SELECT * FROM number_data_types;
The output in the 3rd row, 2nd column is 2.1357987. Since the real data type in PostgreSQL has a precision of 6, the number of digits in a number that can be stored is 6. I expected to see the number 2.13579, because there are 6 digits in the number. What's wrong with my thought?
In my textbook, the author writes: "On the third row, you see PostgreSQL's default behavior in those two columns, which is to output floating-point numbers using their shortest precise decimal representation rather than show the entire value."
The precision on a real is at least 6 digits. From the docs...
On all currently supported platforms, the real type has a range of around 1E-37 to 1E+37 with a precision of at least 6 decimal digits.
When displayed a real (aka float4) can display up to 9 digits.
By default, floating point values are output in text form in their shortest precise decimal representation; the decimal value produced is closer to the true stored binary value than to any other value representable in the same binary precision. (However, the output value is currently never exactly midway between two representable values, in order to avoid a widespread bug where input routines do not properly respect the round-to-nearest-even rule.) This value will use at most 17 significant decimal digits for float8 values, and at most 9 digits for float4 values.
Floating point numbers try to cram a lot of precision into a very small space. As a result they have a lot of quirks.
One of my informatica session behaving weird. For a particular column precision and scale values are defined as 17,16respectively and enable the high precision is on.
As per the precision and scale values it should allow the numbers which are having only single digit before the decimal point but in my session it allowing upto 2digits before the decimal point and failing for 3digits before the decimal point with the error Invalid number
. I am confused why it's allowing 2digits numbers as it should fail for them too?
Ex: precision 17,scale 16
1.4567--allowed
12.4567--allowed
123.4567-- rejected
In addition to it I observed that in the source that column has data type as number but coming to source qualifier same column has data type decimal. Why this internal convertion happened?
Can anyone help on this?
As for the second part of the question: one of Source Qualifier transformation fuctions is to convert any Source data types to PowerCenter data types. Whatever source you will use, Source Qualifier will convert the data types. This way you end up with same data types and comparison between Orace and MS SQL Server won't be a problem.
This is whats happening in case of '12.4567 -- allowed'. Since you have high precision mode on, infa is converting decimal to double automatically. Double is 8byte data. So, if you set something
col(11,9) and trying to insert 1234567890.1, infa will fail.
Summary -
If you specify the precision greater than the maximum number of digits, the Data Integration Service converts decimal values to double in high precision mode.
This is as per Infa documentation
8 bytes (if high precision is off or precision is greater than 38)
16 bytes (if precision <= 18 and high precision is on)
20 bytes (if precision > 18 and <= 28)
24 bytes (if precision > 28 and <= 38)
Decimal value with declared precision and scale. Scale must be less than or equal to precision.
For transformations that support precision up to 38 digits, the precision is 1 to 38 digits, and the scale is 0 to 38.
For transformations that support precision up to 28 digits, the precision is 1 to 28 digits, and the scale is 0 to 28.
If you specify the precision greater than the maximum number of digits, the Data Integration Service converts decimal values to double in high precision mode.
https://docs.informatica.com/data-integration/powercenter/10-2/developer-tool-guide/data-type-reference/transformation-data-types.html
I am new to PG and I'm wondering if I need to 'do anything' extra to properly handle floating-point math.
For example, in ruby you use BigDecimal, and in Elixir you use Decimal.
Is what I have below the best solution for PG?
SELECT
COALESCE(SUM(active_service_fees.service_fee * (1::decimal - active_service_fees.withdraw_percentage_discount)), 0)
FROM active_service_fees
Data types:
service_fee integer NOT NULL
withdraw_percentage_discount numeric(3,2) DEFAULT 0.0 NOT NULL
It depends on what you want.
If you want floating point numbers you need to use the data types real or double precision, depending on your precision requirements.
These floating point numbers need a fixed space (4 or 8 bytes), are stored in binary representation and have limited precision.
If you want arbitrary precision, you can use the binary coded decimal type numeric (decimal is a synonym for it).
Such values are stored as decimal digits, and the amount of storage required depends on the number of digits.
The big advantage of floating point numbers is performance – floating point arithmetic is implemented in hardware in the processor, while arithmetic on binary coded decimals is implemented in PostgreSQL.
A rule of thumb would be:
If you need values that are exact up to a certain number of decimal places (like monetary data) and you don't need to do a lot of calculations, use decimal.
If you need to do number crunching and you don't need values rounded to a fixed precision, use double precision.
what is the use of decimal and numeric datatype in postgreSQL. As per the reference the following is the explanation given to these datatypes.
Decimal,numeric --> It is a user specified precision, exact and range up to 131072 digits before the decimal point and up to 16383 digits after the decimal point.
The above statement shows the description of decimal and numeric datatype. But, still I didn't understand what is the
exact use of these data type and where it is used instead of other datatypes.
Answer with example is much appreciated...
Right from the manual:
The types decimal and numeric are equivalent. Both types are part of the SQL standard.
As for the "why do I need to use it", this is also explained in the manual:
The type numeric can store numbers with a very large number of digits and perform calculations exactly
(Emphasis mine).
If you need numbers with decimals, use decimal (or numeric) if you need numbers without decimals, use integer or bigint. A typical use of decimal as a column type would be a "product price" column or an "interest rate". A typical use of an integer type would be e.g. a column that stores how many products were ordered (assuming you can't order "half" a product).
double and real are also types that can store decimal values, but they are approximate types. This means you don't necessarily retrieve the value you stored. For details please see: http://floating-point-gui.de/
Quoted straight from https://www.postgresql.org/message-id/20211.1325269672#sss.pgh.pa.us
There isn't any difference, in Postgres. There are two type names
because the SQL standard requires us to accept both names. In a quick
look in the standard it appears that the only difference is this:
17)NUMERIC specifies the data type exact numeric, with the decimal
precision and scale specified by the <precision> and <scale>.
18)DECIMAL specifies the data type exact numeric, with the decimal
scale specified by the <scale> and the implementation-defined
decimal precision equal to or greater than the value of the
specified <precision>.
ie, for DECIMAL the implementation is allowed to allow more digits
than requested to the left of the decimal point. Postgres doesn't
exercise that freedom so there's no difference between these types for
us.
regards, tom lane
They are the synonym of each other and functionally same. The SQL:2003 standard says:
21) NUMERIC specifies the data type
exact numeric, with the decimal
precision and scale specified by the
<precision> and <scale>.
22) DECIMAL specifies the data type
exact numeric, with the decimal scale
specified by the <scale> and the
implementation-defined decimal
precision equal to or greater than the
value of the specified <precision>.
Integer and decimal datatype accepts only 10 digits after that getting error message value too large to fit in integer or decimal.What is the maximum limit of integer and decimal datatype in progress 4gl?Is it possible to print 100 digits after decimal place in progress 4gl?
No, it is not possible to print 100 digits after the decimal in Progress. But honestly, why would you?
If you don't need to do that specific calculations you can always use a CHARACTER field.
From the F1-help:
DECIMAL
DECIMAL data consists of decimal numbers up to 50 digits in length
including up to 10 digits to the right of the decimal point.
INTEGER
An INTEGER consists of 32-bit data (whole numbers).
(Integer must be between -2147483648 and 2147483647).
INT64
An INT64 consists of 64-bit data (whole numbers).
(INT64 must be between -9223372036854775808 and 9223372036854775807)
Note that these are absolute limits and has nothing to do with the display format of the variable/field/widget. Display format (FORMAT statement) only affects the possibility to display and can be even more limiting (but can also be overridden programmatically).