SQL對字符串進行排序

假設字符串中只由'A'、'B'、'C'、'D'組成，且長度為7。並設函數REPLICATE(<字符串>,<n>)可以創建一個<字符串>的n個副本的字符串，另外還有REPLACE(<目標字符串>,<老字符串>,<新字符串>)，實現如下：

BEGIN
DECLARE inString CHAR(7);
SET inString = 'DCDBAAB';

REPLICATE('A', (DATA_LENGTH(inString)-DATA_LENGTH(REPLACE(inString,'A',''))))
||
REPLICATE('B', (DATA_LENGTH(inString)-DATA_LENGTH(REPLACE(inString,'B',''))))
||
REPLICATE('C', (DATA_LENGTH(inString)-DATA_LENGTH(REPLACE(inString,'C',''))))
||
REPLICATE('D', (DATA_LENGTH(inString)-DATA_LENGTH(REPLACE(inString,'D',''))))

END;