commit 08caa59ddfeb61a9998e57ebd5d4f8e869147eee Author: Alexander Korotkov Date: Fri May 17 05:47:53 2019 +0300 Improve documentation for array subscription in jsonpath Usage of expressions and multiple ranges in jsonpath array subscription was undocumented. This commit adds locking documentation. diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml index 548cd9da7b6..8944aabf9b0 100644 --- a/doc/src/sgml/json.sgml +++ b/doc/src/sgml/json.sgml @@ -836,17 +836,22 @@ SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @> '{"tags": ["qu [subscript, ...] - - [subscript to last] - - Array element accessor. The provided numeric subscripts return the - corresponding array elements. The first element in an array is - accessed with [0]. The last keyword denotes - the last subscript in an array and can be used to handle arrays - of unknown length. + Array element accessor. subscript + might be given in two forms: expr + or lower_expr to upper_expr. + The first form specifies single array element by its index. The second + form specified array slice by the range of indexes. Zero index + corresponds to first array element. + + + Expression inside subscript may consititue an integer, + numeric expression or any other jsonpath expression + returning single numeric value. The last keyword + can be used in the expression denoting the last subscript in an array. + That's helpful for handling arrays of unknown length.