function中的一个语句,该怎么解决_Oracle管理

function中的一个语句
CREATE FUNCTION "tab"."F_PERCENT" (
"P" DECIMAL(16,10),
"D" INTEGER )
RETURNS CHARACTER(20)
SPECIFIC "SQL120401142399999"
LANGUAGE SQL
NOT DETERMINISTIC
EXTERNAL ACTION
READS SQL DATA
CALLED ON NULL INPUT
INHERIT SPECIAL REGISTERS
begin ATOMIC
declare c char(20);
set c=(
select case when p>=0.01 then
trim(T '.' from trim(B '0' from trim(char(round(p*100,d)))))||'%'
else '0'||trim(T '.' from trim(B '0' from trim(char(round(p*100,d)))))||'%'
end
from SYSIBM.SYSDUMMY1
);
return c;
end;

trim里面的看不懂，请高人指点

------解决方案--------------------

SQL code

TRIM([[LEADING||TRAILING||BOTH] c2 FROM] c1) 如果没有指定任何参数则oracle去除c1头尾空格例如：SELECT TRIM('   WhaT is tHis   ') FROM DUAL;如果指定了c2参数，则oracle去掉c1头尾c2(这个建议细致测试，有多种不同情形的哟)例如：SELECT TRIM('W' FROM 'WhaT is tHis w W') FROM DUAL;如果指定了leading参数则会去掉c1头部c2例如：SELECT TRIM(leading 'W' FROM 'WhaT is tHis w W') FROM DUAL;如果指定了trailing参数则会去掉c1尾部c2例如：SELECT TRIM(trailing 'W' FROM 'WhaT is tHis w W') FROM DUAL;如果指定了both参数则会去掉c1头尾c2(跟不指定有区别吗？没区别！)例如：SELECT TRIM(both 'Wh' FROM 'WhaT is tHis w W') FROM DUAL;注意：c2长度=1
------解决方案--------------------
探讨

SQL code

TRIM([[LEADING||TRAILING||BOTH] c2 FROM] c1) 
如果没有指定任何参数则oracle去除c1头尾空格
例如：SELECT TRIM('   WhaT is tHis   ') FROM DUAL;
如果指定了c2参数，则oracle去掉c1头尾c2(这个建议细致测试，有多种不同情形的哟)
例如：SELECT TRIM('W' FRO……