从varchar SQL Developer中删除前导零 [英] Removing leading zeros from varchar sql developer

问题描述

如何从varchar形式的数字中删除前导零. 我尝试了以下方法:

How would I remove the leading zeros from a number which is in the form of varchar. I have tried the following:

选项1:

insert into example_table (columnName) 
    (SELECT
        SUBSTR(columnName2, InStr('%[^0 ]%', columnName2 + ' '), 10)
        from columnName2);

有了这个，我得到的错误是

With this, the error I get is

SQL Error: ORA-01722: invalid number
ORA-02063: preceding line from xxxx
01722. 00000 -  "invalid number"

选项2:

insert into example_table (columnName) 
    (SELECT
        SUBSTR(columnName2, InStr('%[^0 ]%', columnName2 + ' '),  
        LEN(columnName2))
     from columnName2);

这次我得到

Error at Command Line:23 Column:87
Error report:
SQL Error: ORA-00904: "LEN": invalid identifier

选项3:

SUBSTRING
    (columnName2, PATINDEX('%[^0 ]%', columnName2 + ' '), 10));

类似，我明白了

Error at Command Line:23 Column:41
Error report:
SQL Error: ORA-00904: "PATINDEX": invalid identifier
00904. 00000 -  "%s: invalid identifier"

编辑

我认为修整路线可能是我最好的选择，但是...我不确定如何使用.

I think that the trim route might be my best option, however... I am uncertain how to use it in the case I have.

INSERT INTO temp_table
(columnNeedTrim, column2, column3, column4, column5) 
    SELECT * FROM
        (SELECT(
      SELECT TRIM(leading '0' from columnNeedTrim) FROM table),
            table.column2, 
            table2.column3,
                table.column4
                table.column5
        FROM
        table 
        INNER JOIN 
        table2 ON
            table1.columnNeedTrim=table2.columnNeedTrim) 
    WHERE NOT EXISTS (SELECT * FROM temp_table);

我现在得到一个错误，因为我的修整函数返回了多行结果.

I now get an error because my trim function returns multiple row result.

Error report:
SQL Error: ORA-01427: single-row subquery returns more than one row
01427. 00000 -  "single-row subquery returns more than one row"

我不确定如何对上面的陈述进行修饰(或强制转换).有什么帮助吗? 感谢您的帮助！

I am not sure how to work a trim (or a cast) into the statement above. Any help on that? Thanks for any help!

推荐答案

Oracle对字符串具有内置的TRIM函数.假设您有一个类似'00012345'的字符串，并且想要将其保留为字符串，而不是将其转换为实际的NUMBER，则可以使用

Oracle has built-in TRIM functions for strings. Assuming you have a string like '00012345' and you want to keep it as a string, not convert it to an actual NUMBER, you can use the LTRIM function with the optional second setparameter specifying that you're triming zeros:

select ltrim('000012345', '0') from dual;

LTRIM
-----
12345

如果您还可能有前导空格，则可以一次性修整两者:

If you might also have leading spaces you can trim both in one go:

select ltrim(' 00012345', '0 ') from dual;

LTRIM
-----
12345

您还可以转换成数字并返回，但是除非您想删除其他格式，否则这似乎需要做很多工作:

You could also convert to a number and back, but that seems like a lot of work unless you have other formatting that you want to strip out:

select to_char(to_number('000012345')) from dual;

---

顺便说一句，您第一次尝试得到ORA-01722的直接原因是您使用的是数字+运算符，而不是Oracle的字符串集中运算符||.它正在将您的字符串隐式转换为数字，这似乎是您要避免的操作，并且单个空格的隐式转换-无论是什么用途-都会导致错误. (实际上，您的某些值可能根本不是数字，这是为什么数字应存储在NUMBER字段中的另一个示例；如果是这种情况，那么仍然可以将(转换为)数字转换为数字并返回ORA-01722).如果使用LENGTH而不是LEN，则在第二次尝试中将得到相同的结果.无论如何都不会起作用，因为INSTR无法识别正则表达式.您可以改用REGEXP_INSTR，但是如果您想走这条路，最好使用@schurik的REGEXP_REPLACE版本.

---

Incidentally, the immediate reason you get the ORA-01722 from your first attempt is that you're using the numeric + operator instead of Oracle's string concentenation operator ||. It's doing an implicit conversion of your string to a number, which it seems you're trying to avoid, and the implicit conversion of the single space - whatever that is for - is causing the error. (Possibly some of your values are not, in fact, numbers at all - another example of why numbers should be stored in NUMBER fields; and if that is the case then converting (or casting) to a number and back would still get the ORA-01722). You'd get the same thing in the second attempt if you were using LENGTH instead of LEN. Neither would work anyway as INSTR doesn't recognise regular expressions. You could use REGEXP_INSTR instead, but you'd be better off with @schurik's REGEXP_REPLACE version if you wanted to go down that route.

我不确定我是否理解您的问题编辑内容.看来您的插入内容可以简化为:

I'm not sure I understand your question edit. It looks like your insert can be simplified to:

INSERT INTO temp_table (columnNeedTrim, column2, column3, column4, column5)
SELECT LTRIM(table1.columnNeedTrim, '0 '),
    table1.column2,
    table1.column3,
    table1.column4,
    table1.column5
FROM table1
INNER JOIN table2 ON table2.columnNeedTrim = table1.columnNeedTrim
WHERE NOT EXISTS (
    SELECT * FROM temp_table
    WHERE columnNeedTrim = LTRIM(t42.columnNeedTrim, '0 '));

(我不明白为什么您要在您的版本中执行子查询，或者为什么要从另一个子查询中获得修整后的值.)

(I don't understand why you're doing a subquery in your version, or why you're getting the trimmed value from another subquery.)

您也可以使用MERGE:

MERGE INTO temp_table tt
USING (
    SELECT LTRIM(t42.columnNeedTrim, '0 ') AS columnNeedTrim,
        t42.column2,
        t42.column3,
        t42.column4,
        t42.column5
    FROM t42 
    INNER JOIN t43 ON t43.columnNeedTrim=t42.columnNeedTrim
) sr
ON (sr.columnNeedTrim = tt.columnNeedTrim)
WHEN NOT MATCHED THEN
INSERT (tt.columnNeedTrim, tt.column2, tt.column3, tt.column4, tt.column5)
VALUES (sr.columnNeedTrim, sr.column2, sr.column3, sr.column4, sr.column5);

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