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$JUSTIFY (SQL)

A function that right-aligns a value within a specified width, optionally rounding to a specified number of fractional digits.

Synopsis

$JUSTIFY(expression,width[,decimal])

Description

$JUSTIFY returns the value specified by expression right-aligned within the specified width. You can include the decimal argument to decimal-align numbers within width.

  • $JUSTIFY(expression,width): the 2-argument syntax right-justifies expression within width. It does not perform any conversion of expression. The expression can be a numeric or a nonnumeric string.

  • $JUSTIFY(expression,width,decimal): the 3-argument syntax converts expression to a canonical number, rounds or zero pads fractional digits to decimal, then right-justifies the resulting numeric value within width. If expression is a nonnumeric string or NULL, InterSystems IRIS converts it to 0, pads it, then right-justifies it.

$JUSTIFY recognizes the DecimalSeparator character for the current locale. It adds or deletes a DecimalSeparator character as needed. The DecimalSeparator character depends upon the locale; commonly it is either a period (.) for American-format locales, or a comma (,) for European-format locales. To determine the DecimalSeparator character for your locale, invoke the following method:

  WRITE ##class(%SYS.NLS.Format).GetFormatItem("DecimalSeparator")

SQLCODE -380 is issued if you specify too few arguments. SQLCODE -381 is issued if you specify too many arguments.

$JUSTIFY, ROUND, and TRUNCATE

When rounding to a fixed number of fractional digits is important — for example, when representing monetary amounts — use $JUSTIFY, which returns the specified number of trailing zeros following the rounding operation. When decimal is larger than the number of fractional digits in expression, $JUSTIFY zero-pads. $JUSTIFY also right-aligns the numbers, so that the DecimalSeparator characters align in a column of numbers.

ROUND also rounds to a specified number of fractional digits, but its return value is always normalized, removing trailing zeros. For example, ROUND(10.004,2) returns 10, not 10.00. Unlike $JUSTIFY, ROUND allows you to specify either rounding (the default), or truncation.

TRUNCATE truncates to a specified number of fractional digits. Unlike ROUND, if the truncation results in trailing zeros, these trailing zeros are preserved. However, unlike $JUSTIFY, TRUNCATE does not zero-pad.

ROUND and TRUNCATE allow you to round (or truncate) to the left of the decimal separator. For example, ROUND(128.5,-1) returns 130.

$JUSTIFY and LPAD

The two-argument form of LPAD and the two-argument form of $JUSTIFY both right-align a string by padding it with leading spaces. These two-argument forms differ in how they handle an output width that is shorter than the length of the input expression: LPAD truncates the input string to fit the specified output length. $JUSTIFY expands the output length to fit the input string. This is shown in the following example:

SELECT '>'||LPAD(12345,10)||'<' AS lpadplus,
       '>'||$JUSTIFY(12345,10)||'<' AS justifyplus,
       '>'||LPAD(12345,3)||'<' AS lpadminus,
       '>'||$JUSTIFY(12345,3)||'<' AS justifyminus

The three-argument form of LPAD allows you to left pad with characters other than spaces.

Arguments

expression

The value to be right-justified, and optionally expressed as a numeric with a specified number of fractional digits.

  • If string justification is desired, do not specify decimal. The expression can contain any characters. $JUSTIFY right-justifies expression, as described in width.

  • If numeric justification is desired, specify decimal. If decimal is specified, InterSystems IRIS supplies expression to $JUSTIFY as a canonical number. It resolves leading plus and minus signs and removes leading and trailing zeros. It truncates expression at the first nonnumeric character. If expression begins with a nonnumeric character (such as a currency symbol), InterSystems IRIS converts the expression value to 0. Canonical conversion does not recognize NumericGroupSeparator characters, currency symbols, multiple DecimalSeparator characters, or trailing plus or minus signs. For further details on how InterSystems IRIS converts a numeric to a canonical number, and InterSystems IRIS handling of a numeric string containing nonnumeric characters, refer to Numbers.

    After $JUSTIFY receives expression as a canonical number, $JUSTIFY performs its operation and either rounds or zero-pads this canonical number to decimal number of fractional digits, then right-justifies the result, as described in width.

width

The width in which to right-justify the converted expression. If width is greater than the length of expression (after numeric and fractional digit conversion), InterSystems IRIS right-justifies to width, left-padding as needed with blank spaces. If width is less than the length of expression (after numeric and fractional digit conversion), InterSystems IRIS sets width to the length of the expression value.

Specify width as a positive integer. A width value of 0, the empty string (''), NULL, or a nonnumeric string is treated as a width of 0, which means that InterSystems IRIS sets width to the length of the expression value.

decimal

The number of fractional digits. If expression contains more fractional digits, $JUSTIFY rounds the fractional portion to this number of fractional digits. If expression contains fewer fractional digits, $JUSTIFY pads the fractional portion with zeros to this number of fractional digits, adding a Decimal Separator character, if needed. If decimal=0, $JUSTIFY rounds expression to an integer value and deletes the Decimal Separator character.

If the expression value is less than 1, $JUSTIFY inserts a leading zero before the DecimalSeparator character.

The $DOUBLE values INF, -INF, and NAN are returned unchanged by $JUSTIFY, regardless of the decimal value.

Examples

The following example performs right-justification on strings. No numeric conversion is performed:

SELECT TOP 20 Age,$JUSTIFY(Name,18),DOB FROM Sample.Person

The following example performs numeric right-justification with a specified number of fractional digits:

SELECT TOP 20 $JUSTIFY(Salary,10,2) AS FullSalary,
$JUSTIFY(Salary/7,10,2) AS SeventhSalary FROM Sample.Employee

The following example performs numeric right-justification with a specified number of fractional digits, and string right-justification of the same numeric value:

"SELECT $JUSTIFY({fn ACOS(-1)},8,3) AS ArcCos3,
$JUSTIFY({fn ACOS(-1)},8) AS ArcCosAll

The following Dynamic SQL example performs numeric right-justification with the $DOUBLE values INF and NAN:

  DO ##class(%SYSTEM.Process).IEEEError(0)
  SET x=$DOUBLE(1.2e500)
  SET y=x-x
  SET myquery = 2
  SET myquery(1) = "SELECT $JUSTIFY(?,12,2) AS INFtest,"
  SET myquery(2) = "$JUSTIFY(?,12,2) AS NANtest"
   SET tStatement = ##class(%SQL.Statement).%New()
  SET qStatus = tStatement.%Prepare(.myquery)
    IF qStatus'=1 {WRITE "%Prepare failed:" DO $System.Status.DisplayError(qStatus) QUIT}
  SET rset = tStatement.%Execute(x,y)
  DO rset.%Display()

See Also

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