$ISNULL (check NULL)

$ISNULL determines whether data acquired with the [CSV_COLUMN_NAME] tag is NULL or a 0-byte character.

Organization of this page

Syntax
Values
Status
Example

Syntax

return-value=$ISNULL(column-name)

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Values

return-value

Specifies the name of the variable into which the evaluated results are set. If the value of the column specified by column-name is NULL, 1 is returned; if it is a 0-byte character, 0 is returned.
column-name

Specifies the variable name of the column that is defined by the [CSV_COLUMN_NAME] tag.

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Status

The following table lists and describes the possible statuses:

Status	Description
`NORMAL`	Normal end
`NODATA`	—
`ERROR`	—
Script execution interrupted	An invalid argument was specified, or an error other than the above occurred.

Legend:: —: Not applicable

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Example

The following example acquires data from the file input.csv; it then outputs COLUMN1 IS NULL if COLUMN1 is the NULL character, or outputs COLUMN1 LENGTH IS 0 if COLUMN1 is a 0-byte character:

[SET_VALUE]
  FILENAME = 'input.csv'
  CNT = 1
[CSV_FILE_LOOP]
  FILENAME
  [CSV_COLUMN_NAME]
    COLUMN1 = 1
  [BEGIN]
    [SET_VALUE]
      LEN = $LENGTH(COLUMN1)
    [IF]
      LEN = 0
      [THEN]
        [SET_VALUE]
          VAL=$ISNULL(COLUMN1)
        [IF]
          VAL = 1
          [THEN]
            [SET_VALUE]
              MSG = 'LINE('+CNT+') COLUMN1 IS NULL'
          [ELSE]
            [SET_VALUE]
              MSG = 'LINE('+CNT+') COLUMN1 LENGTH IS 0'
        [IF_END]
 
      [ELSE]
        [SET_VALUE]
          MSG = 'LINE('+CNT+') COLUMN1 LENGTH IS '+LEN
    [IF_END]
    [SET_VALUE]
      $ECHO(MSG)
      CNT = $ADD(CNT,1)
  [END]
 
  [SET_VALUE]
    $SETSTATUS('NORMAL')
[CSV_FILE_LOOP_END]

Contents of input.csv

,bbb,ccc
"",bbb,ccc
aaa,bbb,ccc
"aaa",bbb,ccc

Execution result:

LINE(1) COLUMN1 IS NULL

LINE(2) COLUMN1 LENGTH IS 0

LINE(3) COLUMN1 LENGTH IS 3

LINE(4) COLUMN1 LENGTH IS 3

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