Question

我有2个表，其中包含逗号分隔值的列，我想计算该列的所有相同值，这里是示例表：

import java.util.Scanner;

    public class SerialCheck{
        public static void main (String[] args){

        Scanner sc = new Scanner(System.in);

        System.out.print("How many serial numbers would you like to check: ");
        int length = sc.nextInt();
        int valid = 0;

        String[] sSerials = new String[length];

        for (int nCtr = 0; nCtr < length; nCtr++){
            System.out.print ("Enter Serial " + (nCtr+1) + ": ");
            sSerials[nCtr] = sc.next();
        }

        System.out.println();
        System.out.println("The following were added: ");
            for(int nCtr = 0; nCtr < length; nCtr++){
            System.out.println(sSerials[nCtr]);
        }

        System.out.println();
            for(int nCtr = 0; nCtr < length; nCtr++){
                for (int x = 0; x < sSerials[nCtr].length(); x++){
                    char c = sSerials[nCtr].charAt(x);

                if((sSerials[nCtr].charAt(x)!='a') || 
                   (sSerials[nCtr].charAt(x)!='b') || 
                   (sSerials[nCtr].charAt(x)!='c') ||
                   (sSerials[nCtr].charAt(x)!='-') ||
                   (sSerials[nCtr].charAt(x)!='.')){
                    valid--;
                } 
                else{
                    valid++;
                }
            }
            if (valid < 0 && sSerials[nCtr].length() != 14){
                System.out.println("The address is invalid.");
            }
            else{
                System.out.println("The address is valid.");
            }

        }

    }
}

现在，您有任何想法或建议，以便我能实现吗？比如添加新表或者单个查询是否可以这样做？

Answer 1

尝试此查询

SELECT LENGTH(COLUMN) - LENGTH(REPLACE(COLUMN, ',', '')) FROM TABLE_NAME

在一列mysql中计算所有相同的逗号分隔值

1 个答案: