在我的数据库中，我有这两个表：
人
+----+---------+---------+
| pk | name | sirname |
+----+---------+---------+
| 1 | john | leno |
| 2 | william | wallice |
| 3 | eva | apple |
| 4 | walter | white |
+----+---------+---------+
请求
+----+-------------+----------+---------------+---------+---------+
| pk | requestdate | accepted | requestperson | parent1 | parent2 |
+----+-------------+----------+---------------+---------+---------+
| 1 | 1/1/2014 | Y | 1 | 2 | 3 |
| 2 | 1/2/2014 | N | 4 | NULL | NULL |
+----+-------------+----------+---------------+---------+---------+
要收到我的请求：
SELECT *
FROM request
LEFT JOIN person p_subject ON requestperson = p_subject.pk
LEFT JOIN person p_parent1 ON parent1 = p_parent1.pk
LEFT JOIN person p_parent2 ON parent2 = p_parent2.pk
这很完美，但是当我想创建一个VIEW时：
CREATE VIEW v_request AS
SELECT *
FROM request
LEFT JOIN person p_subject ON requestperson = p_subject.pk
LEFT JOIN person p_parent1 ON parent1 = p_parent1.pk
LEFT JOIN person p_parent2 ON parent2 = p_parent2.pk
我收到此错误：ORA-00957: duplicate column name
我不想手动重命名所有列。我该如何解决这个问题？
答案 0 :(得分：2)
您的观点包括：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <fcntl.h>
//sys variables
char Input[100], commandLogin[100], Output[100], Username[50], possibleUsername[50];
int readDescriptor, logEval;
int readDescriptor2;
pid_t childPid;
//
int commandCatcher(){
//define socket
int socketOne[2], socketTwo[2];
if(socketpair(AF_UNIX, SOCK_STREAM, 0, socketOne) < 0){
perror("socket - err");
exit(0);
}
if(logEval == 0)
switch(fork()){//first child
case -1:
perror("fork - err");
exit(1);
case 0:
childPid=getpid();
readDescriptor = read(socketOne[0], commandLogin, sizeof(commandLogin));
if (strcmp(commandLogin, "login") == 0 ){
printf("Log eval from first:%d\n", logEval);
write(socketOne[0], "ok", strlen("ok") + 1);
//something to do here so that the child knows it was given the username
exit(logEval);
}
else {
printf("Try again.\n");
write(socketOne[0], "none", strlen("none")+1);
exit(1);
}
}
if(logEval == 1){
switch(fork()){//verify username
case -1:
perror("fork - err");
exit(2);
case 0:
readDescriptor2 = read(socketTwo[0], possibleUsername, sizeof(possibleUsername));
printf("Username from second child:%s ---\n", possibleUsername);
printf("logEval is : %d\n", logEval);
}
exit(2);
}
//parent
//getting initial value
scanf("%s", Input);
//writing initial value
write(socketOne[1], Input, strlen(Input)+1);
readDescriptor = read(socketOne[1], Output, sizeof(Output));
//printf("output %s\n", Output);
//verify if the command was correctly given
if(strcmp(Output, "ok") == 0) {
printf("Command was accepted. Insert your username: %d\n", logEval);
if(socketpair(AF_UNIX, SOCK_STREAM, 0, socketTwo) < 0){//second socket
perror("sockettwo - err");
exit(2);
}
scanf("%s", Username);
write(socketTwo[1], Username, strlen(Username)+1);
logEval = 1;
commandCatcher();
}
else if(strcmp(Output, "none") == 0) {
printf("Command was denied. Please try again:\n");
commandCatcher();//recursive call
}
wait(&logEval);
printf("execution finished");
}
int main(){
printf("Welcome to Sys v1.0. To start off, please insert your command. \n");
commandCatcher();
return 0;
}
pk的三列（不是一个好的列名）name 因为tablealiases不会自动添加（错误sirname确切地说明）
我确信您必须手动将其重命名为ORA-00957: duplicate column name，subject_pk，subject_name，依此类推。