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kenorb
Asked: 2020-10-24 11:10:57 +0800 CST

如何从单个列中提取证书属性并拆分为多个？

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在我的表中，我有一个cert_attr存储Certificate X.509 Attributes的字段（比如说） 。

这是 3 行的示例（每行对应一个字段）：

"CN=User1, OU=Eng, O=Company Ltd, L=D4, S=Dublin, C=IE"
"CN=User2, OU=Eng, O=Company Ltd, L=D2, S=Dublin, C=IE"
"OU=Eng, O=Company Ltd"

我正在尝试使用SELECT以下方式将字段的值拆分为单独的列：

SELECT
SUBSTRING_INDEX(SUBSTRING_INDEX(cert_attr, "CN=", -1), ", ", 1) as CN,
SUBSTRING_INDEX(SUBSTRING_INDEX(cert_attr, "OU=", -1), ", ", 1) as OU,
SUBSTRING_INDEX(SUBSTRING_INDEX(cert_attr, "O=", -1), ", ", 1) as O,
SUBSTRING_INDEX(SUBSTRING_INDEX(cert_attr, "L=", -1), ", ", 1) as L,
SUBSTRING_INDEX(SUBSTRING_INDEX(cert_attr, "ST=", -1), ", ", 1) as ST,
SUBSTRING_INDEX(SUBSTRING_INDEX(cert_attr, "C=", -1), ", ", 1) as C
FROM mytable

这可行，但是缺少某些属性的行存在问题。

因此，在字段字符串中缺少属性的情况下，我希望该列为空，但它会返回整个字符串。

前两行示例按预期工作，正确返回以下列：

| CN    | OU  | O           | L  | S.     | C  |
| ----- | --- | ----------- | -- | ------ | -- |
| User1 | Eng | Company Ltd | D4 | Dublin | IE |
| User2 | Eng | Company Ltd | D2 | Dublin | IE |

问题在于第 3 行示例，我希望在找不到子字符串模式时返回一个空字符串：

| CN         | OU  | O           | L          | S.         | C          |
| ---------- | --- | ----------- | ---------- | ---------- | ---------- |
| OU=Eng,... | Eng | Company Ltd | OU=Eng,... | OU=Eng,... | OU=Eng,... |

而是返回整个字符串。

问题：

SUBSTRING_INDEX()当找不到子字符串时，有什么方法可以返回一个空字符串？或者也许还有其他功能（如正则表达式）或其他解决方法？

我的目标是通过将这些属性放在具有有效值的单独列中来将数据提取到 TSV 文件中：

mysql mytable < query.sql > cert_attributes.tsv
mysql regex

1 个回答

  1. Best Answer

    第一部分只是向您展示该程序有效

    CREATE tABLE tablecertificate  (
stationery_name varchar(500) 

    INSERT INTO tablecertificate values 
("CN=User1, OU=Eng, O=Company Ltd, L=D4, S=Dublin, C=IE"),
("CN=User2, OU=Eng, O=Company Ltd, L=D2, S=Dublin, C=IE"),
("OU=Eng, O=Company Ltd")

    CREATE PROCEDURE `splitcertifcate`()
BEGIN
 DECLARE current_pos INT DEFAULT 1;
 DECLARE delim CHAR DEFAULT ',';
 DECLARE current VARCHAR(100) DEFAULT '';
 DECLARE CN VARCHAR(100) DEFAULT '';
 DECLARE OU VARCHAR(100) DEFAULT '';
 DECLARE O VARCHAR(100) DEFAULT '';
 DECLARE L VARCHAR(100) DEFAULT '';
 DECLARE S VARCHAR(100) DEFAULT '';
 DECLARE C VARCHAR(100) DEFAULT '';
 DECLARE rest_cert_part VARCHAR(100) DEFAULT '';
 DECLARE current_cert_part  VARCHAR(100) DEFAULT '';
  DECLARE finished INTEGER DEFAULT 0;
  DECLARE certificate varchar(500) DEFAULT "";
  DEClARE curcertificate 
      CURSOR FOR 
          SELECT stationery_name FROM tablecertificate;

  -- declare NOT FOUND handler
  DECLARE CONTINUE HANDLER 
        FOR NOT FOUND SET finished = 1;
        
        
  #Temporary Table that holds the splittet part
   DROP TEMPORARY TABLE IF EXISTS mycertificate;
  CREATE TEMPORARY TABLE mycertificate(CN VARCHAR(100), OU VARCHAR(100), O VARCHAR(100) , L  VARCHAR(100), S VARCHAR(100), C VARCHAR(100));

  OPEN curcertificate;
    getcertificate: LOOP
      # get first row elemnt
      FETCH curcertificate INTO certificate;
      IF finished = 1 THEN 
          #Last element reached
          LEAVE getcertificate;
      END IF;
        SET CN = '';
        SET OU = '';
        SET O = '';
        SET L = '';
        SET S = '';
        SET C = '';
      SET current_pos =  LOCATE(delim,certificate);
        SET current_cert_part = SUBSTRING(certificate,1,current_pos-1);
      SET rest_cert_part = SUBSTRING(certificate from current_pos+1);
        IF length(trim(current_cert_part)) = 0   THEN
          SET current_cert_part = rest_cert_part;
      END IF;
      #Examine first element of the string
        CASE 
          WHEN INSTR(current_cert_part, "CN=")  > 0 THEN SET CN = TRIM(current_cert_part);
          WHEN INSTR(current_cert_part, "OU=")  > 0 THEN SET OU = TRIM(current_cert_part);
          WHEN INSTR(current_cert_part, "O=")  > 0 THEN SET O = TRIM(current_cert_part);
          WHEN INSTR(current_cert_part, "L=")  > 0 THEN SET L = TRIM(current_cert_part);
          WHEN INSTR(current_cert_part, "S=")  > 0 THEN SET S = TRIM(current_cert_part);
          WHEN INSTR(current_cert_part, "C=")  > 0 THEN SET C = TRIM(current_cert_part);
        END CASE;
        WHILE current_pos <> 0 DO
          #loop throuigh the string
          set  current_pos = LOCATE(delim,rest_cert_part);
          set current_cert_part = SUBSTRING(rest_cert_part,1,current_pos-1);
          set rest_cert_part = SUBSTRING(rest_cert_part from current_pos+1);

          if length(trim(current_cert_part)) = 0   then
              #ÖLast elemnt in string
              set current_cert_part = rest_cert_part;
          end if;    
          CASE 
              WHEN INSTR(current_cert_part, "CN=")  > 0 THEN SET CN = TRIM(current_cert_part);
              WHEN INSTR(current_cert_part, "OU=")  > 0 THEN SET OU = TRIM(current_cert_part);
              WHEN INSTR(current_cert_part, "O=")  > 0 THEN SET O = TRIM(current_cert_part);
              WHEN INSTR(current_cert_part, "L=")  > 0 THEN SET L = TRIM(current_cert_part);
              WHEN INSTR(current_cert_part, "S=")  > 0 THEN SET S = TRIM(current_cert_part);
              WHEN INSTR(current_cert_part, "C=")  > 0 THEN SET C = TRIM(current_cert_part);
          END CASE;
      END WHILE;
        #In sert splittet strung  row in temp table
       INSERT INTO mycertificate VALUES (  CN,OU,O,L,S,C);


  END LOOP getcertificate;
  CLOSE curcertificate;
SELECT * FROM mycertificate;
END

    cALL splitcertifcate();

    中文 | 欧 | ○ | 大号 | 小号 | C   
:------- | :----- | :------------ | :--- | :------- | :---
CN=用户1 | 欧=英| O=有限公司| L=D4 | S=都柏林 | C=IE
CN=用户2 | 欧=英| O=有限公司| L=D2 | S=都柏林 | C=IE
         | 欧=英| O=有限公司| | |     

✓

    db<>在这里摆弄

    完整的存储过程，包括生成 tsv 文件

    DELIMITER //
CREATE DEFINER=`root`@`%` PROCEDURE `splitcertifcate`()
BEGIN
 DECLARE current_pos INT DEFAULT 1;
 DECLARE delim CHAR DEFAULT ',';
 DECLARE current VARCHAR(100) DEFAULT '';
 DECLARE CN VARCHAR(100) DEFAULT '';
 DECLARE OU VARCHAR(100) DEFAULT '';
 DECLARE O VARCHAR(100) DEFAULT '';
 DECLARE L VARCHAR(100) DEFAULT '';
 DECLARE S VARCHAR(100) DEFAULT '';
 DECLARE C VARCHAR(100) DEFAULT '';
 DECLARE rest_cert_part VARCHAR(100) DEFAULT '';
 DECLARE current_cert_part  VARCHAR(100) DEFAULT '';
    DECLARE finished INTEGER DEFAULT 0;
    DECLARE certificate varchar(500) DEFAULT "";
    DEClARE curcertificate 
        CURSOR FOR 
            SELECT stationery_name FROM tablecertificate;

    -- declare NOT FOUND handler
    DECLARE CONTINUE HANDLER 
        FOR NOT FOUND SET finished = 1;
        
    #Temporary Table that holds the splittet part
     DROP TEMPORARY TABLE IF EXISTS mycertificate;
    CREATE TEMPORARY TABLE mycertificate(CN VARCHAR(100), OU VARCHAR(100), O VARCHAR(100) , L  VARCHAR(100), S VARCHAR(100), C VARCHAR(100));

    OPEN curcertificate;
    getcertificate: LOOP
        # get first row elemnt
        FETCH curcertificate INTO certificate;
        IF finished = 1 THEN 
            #Last element reached
            LEAVE getcertificate;
        END IF;
        SET CN = '';
        SET OU = '';
        SET O = '';
        SET L = '';
        SET S = '';
        SET C = '';
        SET current_pos =  LOCATE(delim,certificate);
        SET current_cert_part = SUBSTRING(certificate,1,current_pos-1);
        SET rest_cert_part = SUBSTRING(certificate from current_pos+1);
        IF length(trim(current_cert_part)) = 0   THEN
            SET current_cert_part = rest_cert_part;
        END IF;
        #Examine first element of the string
        CASE 
            WHEN INSTR(current_cert_part, "CN=")  > 0 THEN SET CN = TRIM(current_cert_part);
            WHEN INSTR(current_cert_part, "OU=")  > 0 THEN SET OU = TRIM(current_cert_part);
            WHEN INSTR(current_cert_part, "O=")  > 0 THEN SET O = TRIM(current_cert_part);
            WHEN INSTR(current_cert_part, "L=")  > 0 THEN SET L = TRIM(current_cert_part);
            WHEN INSTR(current_cert_part, "S=")  > 0 THEN SET S = TRIM(current_cert_part);
            WHEN INSTR(current_cert_part, "C=")  > 0 THEN SET C = TRIM(current_cert_part);
        END CASE;
        WHILE current_pos <> 0 DO
            #loop throuigh the string
            set  current_pos = LOCATE(delim,rest_cert_part);
            set current_cert_part = SUBSTRING(rest_cert_part,1,current_pos-1);
            set rest_cert_part = SUBSTRING(rest_cert_part from current_pos+1);

            if length(trim(current_cert_part)) = 0   then
                #ÖLast elemnt in string
                set current_cert_part = rest_cert_part;
            end if;    
            CASE 
                WHEN INSTR(current_cert_part, "CN=")  > 0 THEN SET CN = TRIM(current_cert_part);
                WHEN INSTR(current_cert_part, "OU=")  > 0 THEN SET OU = TRIM(current_cert_part);
                WHEN INSTR(current_cert_part, "O=")  > 0 THEN SET O = TRIM(current_cert_part);
                WHEN INSTR(current_cert_part, "L=")  > 0 THEN SET L = TRIM(current_cert_part);
                WHEN INSTR(current_cert_part, "S=")  > 0 THEN SET S = TRIM(current_cert_part);
                WHEN INSTR(current_cert_part, "C=")  > 0 THEN SET C = TRIM(current_cert_part);
            END CASE;
        END WHILE;
        #In sert splittet strung  row in temp table
       INSERT INTO mycertificate VALUES (  CN,OU,O,L,S,C);


    END LOOP getcertificate;
    CLOSE curcertificate;

    SELECT * FROM mycertificate INTO OUTFILE "C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/cert.tsv"
    FIELDS TERMINATED BY '\t'
    ENCLOSED BY '"'
    LINES TERMINATED BY '\n';
END//
DELIMITER ;

    结果 tsv 文件

    "CN=User1"  "OU=Eng"    "O=Company Ltd" "L=D4"  "S=Dublin"  "C=IE"
"CN=User2"  "OU=Eng"    "O=Company Ltd" "L=D2"  "S=Dublin"  "C=IE"
""          "OU=Eng"    "O=Company Ltd"  ""       ""        ""

    您必须检查 INTO OUTFILE 文件夹，该文件夹必须与 my.ini/cnf 文件中的条目相对应

    secure-file-priv='C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/'
    • 1

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