Decode of SQL

SELECT * from A ORDER by DECODE (Aa, NULL,Ab) ;

Aa Ab

--------    ----------

1 19

< Strong> < Strong> < Strong> null        2

3 1

4 10

with decode When a function's statement is sorted, it is found that the AA field in a row is null when it is given a Span style= "Font-size:medium" > the AA field, therefore Span style= "font-size:14px" > aa field participates in sorting by this value.

In the Redshift database:

1.select carr_cd, DECODE (CARR_CD, ' JL ', ' Jo ', CARR_CD) from the Order by DECODE (CARR_CD, ' JL ', ' Jo ', carr_cd), CARR_CD; Wrong ambiguous

2.select carr_cd, DECODE (carr_cd, ' JL ', ' JO ', CARR_CD) from A order by CARR_CD; Wrong ambiguous

3.select DECODE (CARR_CD, ' JL ', ' Jo ', carr_cd) from A Order by DECODE (CARR_CD, ' JL ', ' Jo ', CARR_CD); Right

4.select CARR_CD from A order by DECODE (CARR_CD, ' JL ', ' JO ', carr_cd), CARR_CD; Right

Decode of SQL