SQL statement for row-to-column merge

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SQL > create table test (id number,name varchar2 (20))

SQL > insert into test values (1)

SQL > insert into test values (1)

SQL > insert into test values (1)

SQL > insert into test values (2)

SQL > insert into test values (2)

SQL > commit

Effect 1: row to column

SQL > select wm_concat (name) from test

WM_CONCAT (NAME)

A,b,c,d,e

Effect 2: replace the comma in the result with "|"

SQL > select replace (wm_concat (name),'|') from test

REPLACE (WM_CONCAT (NAME),'|')

A | b | c | d | e

Effect 3: merge name in groups by ID

SQL > select id,wm_concat (name) name from test group by id

ID NAME

1 a,b,c

2 d,e

Lazy extended usage:

Example: I want to write a view, similar to "create or replace view as select field 1. Field 50 from tablename", the base table has more than 50 fields, if it is too troublesome to write by hand, is there any easy way? Of course there is. Look if I apply wm_concat to make this requirement simple.

SQL > select 'create or replace view as select' | | wm_concat (column_name) | | 'from dept'from user_tab_columns where table_name='DEPT'

'CREATEORREPLACEVIEWASSELECT' | | WM_CONCAT (COLUMN_NAME) | |' FROMDEPT'

Create or replace view as select DEPTNO,DNAME,LOC from dept

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