SELECT
CASE
WHEN A.TYPE='SUTDENT' THEN
A.NAME,A.AGE,B.GRADE
WHEN A.TYPE='TEACHER' THEN
A.NAME,A.AGE,C.GRADE
END
FROM PERSON A,STUDENT B,TEACHER C
WHERE A.PID=B.PID AND A.PID=C.PID这个提示 A.NAME 这儿缺少关键字 怎么回事啊
CASE
WHEN A.TYPE='SUTDENT' THEN
A.NAME,A.AGE,B.GRADE
WHEN A.TYPE='TEACHER' THEN
A.NAME,A.AGE,C.GRADE
END
FROM PERSON A,STUDENT B,TEACHER C
WHERE A.PID=B.PID AND A.PID=C.PID这个提示 A.NAME 这儿缺少关键字 怎么回事啊
A.NAME,A.AGE,
CASE
WHEN A.TYPE='SUTDENT' THEN
B.GRADE
WHEN A.TYPE='TEACHER' THEN
C.GRADE
END case
FROM PERSON A,STUDENT B,TEACHER C
WHERE A.PID=B.PID AND A.PID=C.PID
WHEN A.TYPE='SUTDENT' THEN 这里会提示未找到预期FROM关键字 。。
CASE WHEN A.TYPE='SUTDENT' THEN A.NAME||','||A.AGE||',||B.GRADE
WHEN A.TYPE='TEACHER' THEN A.NAME||','||A.AGE||','||C.GRADE END
FROM PERSON A,STUDENT B,TEACHER C
WHERE A.PID=B.PID AND A.PID=C.PID