How to handle 0E-8 in sql-CodePudding

One of my column was havng value 0.0000000 it seems and it turns 0E-8 when am extracting data.ow to handle this.I have tried below commands in hive.

round(column,8) as amount
cast(column as decimal(10,8)) as amount

The above 2 doesnt working as expected

CodePudding user response：

In SQL, you can handle very small numbers such as 0E-8 by using the ROUND function. For example, you can use the following query to round 0E-8 to the nearest hundredth:

SELECT ROUND(0E-8, 2)

This will return 0.00.

You can also use the FORMAT function to format the number as a string with a specific number of decimal places. For example, the following query will format 0E-8 with two decimal places:

SELECT FORMAT(0E-8, '0.00')

This will return '0.00'.

If you want to store very small numbers in a database, you may need to use a data type that supports a larger range of values, such as FLOAT or DOUBLE PRECISION.

CodePudding user response：

Use the format_number function:

SELECT format_number(column, 8) as amount FROM my_table;

This function will format the number as a string with the specified number of decimal places.

SELECT round(column, 8) as amount FROM my_table;

Used the round function with a larger number of decimal places ,This will round the number to the specified number of decimal places, but it may not work if the number of significant digits is larger than the number of decimal places.

SELECT cast(column as decimal(10, 8)) as amount FROM my_table;

Used the cast function to specify the desired number of decimal places This will cast the number as a decimal with the specified number of decimal places.

It's worth noting that these solutions may not work if the original value is actually 0, as the number will still be represented as 0 in scientific notation. In this case, you may need to use a different approach, such as using the if function to check for a value of 0 and handle it appropriately.

If you are using the round() function and the value in the column is being rounded to 0, it could be because the number of decimal places specified in the round() function is too high. For example, if the value in the column is 0.00000001 and you are using the round() function with a precision of 8 decimal places, the value will be rounded to 0.00000000.

You can try using the format() function to display the value with a specific number of decimal places. The syntax for the format() function is:

format(value, format)

The value is the numeric value that you want to format, and the format is a string that specifies the format of the output. To specify the number of decimal places, you can use the f format specifier followed by the number of decimal places. For example, the following statement will format the value in the amount column with 8 decimal places:

SELECT format(amount, 'f8') AS amount FROM my_table;

If you are using the cast() function and the value is being displayed as 0E-8, it could be because the value is being treated as a floating point number and is being displayed in scientific notation. In this case, you can try using the decimal() function to cast the value to a decimal data type with a specific precision and scale. The syntax for the decimal() function is similar to the cast() function:

decimal(precision, scale)

The precision is the total number of digits in the decimal number, and the scale is the number of digits to the right of the decimal point. For example, the following statement will cast the value in the amount column to a decimal with a precision of 10 and a scale of 8

SELECT cast(amount as decimal(10, 8)) AS amount FROM my_table;

This will ensure that the value is displayed with the specified number of decimal places, rather than in scientific notation.