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Attached is an update to contrib/tablefunc. It introduces a new
function, connectby(), which can serve as a reference implementation for the changes made in the last few days -- namely the ability of a function to return an entire tuplestore, and the ability of a function to make use of the query provided "expected" tuple description. Description: connectby(text relname, text keyid_fld, text parent_keyid_fld, text start_with, int max_depth [, text branch_delim]) - returns keyid, parent_keyid, level, and an optional branch string - requires anonymous composite type syntax in the FROM clause. See the instructions in the documentation below. Joe Conway
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‎contrib/tablefunc/README.tablefunc

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@@ -60,6 +60,12 @@ Installation:
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- requires anonymous composite type syntax in the FROM clause. See
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the instructions in the documentation below.
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connectby(text relname, text keyid_fld, text parent_keyid_fld,
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text start_with, int max_depth [, text branch_delim])
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- returns keyid, parent_keyid, level, and an optional branch string
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- requires anonymous composite type syntax in the FROM clause. See
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the instructions in the documentation below.
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Documentation
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==================================================================
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Name
@@ -324,6 +330,109 @@ AS ct(row_name text, category_1 text, category_2 text, category_3 text);
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test2 | val6 | val7 |
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(2 rows)
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==================================================================
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Name
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connectby(text, text, text, text, int[, text]) - returns a set
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representing a hierarchy (tree structure)
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Synopsis
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connectby(text relname, text keyid_fld, text parent_keyid_fld,
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text start_with, int max_depth [, text branch_delim])
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Inputs
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relname
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Name of the source relation
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keyid_fld
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Name of the key field
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parent_keyid_fld
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Name of the key_parent field
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start_with
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root value of the tree input as a text value regardless of keyid_fld type
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max_depth
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zero (0) for unlimited depth, otherwise restrict level to this depth
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branch_delim
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if optional branch value is desired, this string is used as the delimiter
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Outputs
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Returns setof record, which must defined with a column definition
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in the FROM clause of the SELECT statement, e.g.:
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0, '~')
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AS t(keyid text, parent_keyid text, level int, branch text);
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- or -
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0)
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AS t(keyid text, parent_keyid text, level int);
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Notes
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1. keyid and parent_keyid must be the same data type
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2. The column definition *must* include a third column of type INT4 for
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the level value output
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3. If the branch field is not desired, omit both the branch_delim input
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parameter *and* the branch field in the query column definition
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4. If the branch field is desired, it must be the forth column in the query
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column definition, and it must be type TEXT
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Example usage
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CREATE TABLE connectby_tree(keyid text, parent_keyid text);
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INSERT INTO connectby_tree VALUES('row1',NULL);
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INSERT INTO connectby_tree VALUES('row2','row1');
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INSERT INTO connectby_tree VALUES('row3','row1');
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INSERT INTO connectby_tree VALUES('row4','row2');
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INSERT INTO connectby_tree VALUES('row5','row2');
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INSERT INTO connectby_tree VALUES('row6','row4');
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INSERT INTO connectby_tree VALUES('row7','row3');
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INSERT INTO connectby_tree VALUES('row8','row6');
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INSERT INTO connectby_tree VALUES('row9','row5');
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-- with branch
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0, '~')
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AS t(keyid text, parent_keyid text, level int, branch text);
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keyid | parent_keyid | level | branch
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-------+--------------+-------+---------------------
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row2 | | 0 | row2
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row4 | row2 | 1 | row2~row4
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row6 | row4 | 2 | row2~row4~row6
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row8 | row6 | 3 | row2~row4~row6~row8
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row5 | row2 | 1 | row2~row5
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row9 | row5 | 2 | row2~row5~row9
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(6 rows)
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-- without branch
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0)
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AS t(keyid text, parent_keyid text, level int);
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keyid | parent_keyid | level
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-------+--------------+-------
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row2 | | 0
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row4 | row2 | 1
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row6 | row4 | 2
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row8 | row6 | 3
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row5 | row2 | 1
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row9 | row5 | 2
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(6 rows)
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==================================================================
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-- Joe Conway
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‎contrib/tablefunc/tablefunc-test.sql

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--
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-- show_all_settings()
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--
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SELECT * FROM show_all_settings();
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--
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-- normal_rand()
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--
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select * from crosstab('select rowid, attribute, value from ct where rowclass = ''group1'' order by 1,2;', 2) as c(rowid text, att1 text, att2 text);
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select * from crosstab('select rowid, attribute, value from ct where rowclass = ''group1'' order by 1,2;', 3) as c(rowid text, att1 text, att2 text, att3 text);
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select * from crosstab('select rowid, attribute, value from ct where rowclass = ''group1'' order by 1,2;', 4) as c(rowid text, att1 text, att2 text, att3 text, att4 text);
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-- test connectby with text based hierarchy
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DROP TABLE connectby_tree;
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CREATE TABLE connectby_tree(keyid text, parent_keyid text);
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INSERT INTO connectby_tree VALUES('row1',NULL);
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INSERT INTO connectby_tree VALUES('row2','row1');
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INSERT INTO connectby_tree VALUES('row3','row1');
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INSERT INTO connectby_tree VALUES('row4','row2');
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INSERT INTO connectby_tree VALUES('row5','row2');
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INSERT INTO connectby_tree VALUES('row6','row4');
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INSERT INTO connectby_tree VALUES('row7','row3');
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INSERT INTO connectby_tree VALUES('row8','row6');
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INSERT INTO connectby_tree VALUES('row9','row5');
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-- with branch
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0, '~') AS t(keyid text, parent_keyid text, level int, branch text);
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-- without branch
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0) AS t(keyid text, parent_keyid text, level int);
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-- test connectby with int based hierarchy
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DROP TABLE connectby_tree;
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CREATE TABLE connectby_tree(keyid int, parent_keyid int);
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INSERT INTO connectby_tree VALUES(1,NULL);
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INSERT INTO connectby_tree VALUES(2,1);
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INSERT INTO connectby_tree VALUES(3,1);
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INSERT INTO connectby_tree VALUES(4,2);
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INSERT INTO connectby_tree VALUES(5,2);
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INSERT INTO connectby_tree VALUES(6,4);
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INSERT INTO connectby_tree VALUES(7,3);
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INSERT INTO connectby_tree VALUES(8,6);
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INSERT INTO connectby_tree VALUES(9,5);
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-- with branch
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', '2', 0, '~') AS t(keyid int, parent_keyid int, level int, branch text);
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-- without branch
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SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', '2', 0) AS t(keyid int, parent_keyid int, level int);
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