Write the sql query to find largest value in row wise without using great

Question

write the sql query to find largest value in row wise without using
greatest fuction?

Answer 1

Another not so good way, considering you want greatest of 4 fields from a single record:
SQL> ed
Wrote file afiedt.buf
  1  with t as (Select 100 col1,200 col2,300 col3,400 col4 from dual
  2  union select 500,600,700,800 from dual
  3  union select 900,1000,1100,1200 from dual
  4  union select 1300,1400,1500,1600 from dual
  5  union select 1700,1800,1900,2000 from dual
  6  union select 2100,2200,2300,2400 from dual
  7  union select 2800,2700,2600,2500 from dual
  8  union select 2900,3000,3100,3200 from dual)
  9  SELECT (CASE WHEN col1 > col2 THEN col1 ELSE col2 END) Max_value
10  FROM
11  (SELECT (CASE WHEN col1_col2 > col2_col3 THEN col1_col2 ELSE col2_col3 END) col1,
12         (CASE WHEN col2_col3 > col3_col4 THEN col2_col3 ELSE col3_col4 END) col2,
13         (CASE WHEN col3_col4 > col4_col1 THEN col3_col4 ELSE col4_col1 END) col3
14  FROM
15  (SELECT (CASE WHEN col1 > col2 THEN col1 ELSE col2 END) col1_col2,
16         (CASE WHEN col2 > col3 THEN col2 ELSE col3 END) col2_col3,
17         (CASE WHEN col3 > col4 THEN col3 ELSE col4 END) col3_col4,
18         (CASE WHEN col4 > col1 THEN col4 ELSE col1 END) col4_col1
19* FROM t))
SQL> /
MAX_VALUE
       400
       800
      1200
      1600
      2000
      2400
      2800
      3200
8 rows selected.
SQL> Edited by: AP on Sep 21, 2010 6:29 AM