VARIABLE_COLUMN_LOG_PARSE - Amazon Kinesis Data Analytics
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VARIABLE_COLUMN_LOG_PARSE(  <character-expression>, <columns>, <delimiter-string>  [ , <escape-string>, <quote-string> ] )  <columns> := <number of columns> | <list of columns>  <number of columns> := <numeric value expression>  <list of columns> := '<column description>[, ...]'  <column description> := <identifier> TYPE <data type> [ NOT NULL ]  <delimiter string> := <character-expression>  <escape-string> := <character-expression>  <quote-string> := '<begin quote character> [ <end quote character> ]'

VARIABLE_COLUMN_LOG_PARSE splits an input string (its first argument, <character-expression>) into fields separated by a delimiter character or delimiter string. Thus it handles comma-separated values or tab-separated values. It can be combined with FIXED_COLUMN_LOG_PARSE to handle something like maillog, where some fields are fixed-length and others are variable-length.


Parsing of binary files is not supported.

The arguments <escape-string> and <quote-string> are optional. Specifying an <escape-string> allows the value of a field to contain an embedded delimiter. As a simple example, if the <delimiter-string> specified a comma, and the <escape-string> specified a backslash, then an input of "a,b' would be split into two fields "a" and "b", but an input of "a\,b" would result in a single field "a,b".

Since Amazon Kinesis Data Analytics supports Expressions and Literals, a tab can also be a delimiter, specified using a unicode escape, e.g., u&'\0009', which is a string consisting only of a tab character.

Specifying a <quote-string> is another way to hide an embedded delimiter. The <quote-string> should be a one or two character expression: the first is used as the <begin quote character> character; the second, if present, is used as the <end quote character> character. If only one character is supplied, it is used as both to begin and to end quoted strings. When the input includes a quoted string, that is, a string enclosed in the characters specified as <quote-string>, then that string appears in one field, even if it contains a delimiter.

Note that the <begin quote character> and <end quote character> are single characters and can be different. The <begin quote character> can be used to start and end the quoted string, or the <begin quote character> can start the quoted string and the <end quote character> used to end that quoted string.

When a list of columns <list of columns> is supplied as the second parameter <columns>, the column specifications (<column description>) for types DATE, TIME, and TIMESTAMP support a format parameter allowing the user to specify exact time component layout. The parser uses the Java class java.lang.SimpleDateFormat to parse the strings for those types. Date and Time Patterns gives a full description of timestamp format strings, with examples. The following is an example of a column definition with a format string:

   "name" TYPE TIMESTAMP 'dd/MMM/yyyy:HH:mm:ss'

By default, the output columns are named COLUMN1, COLUMN2, COLUMN3, etc., each of SQL data type VARCHAR(1024).