How do I escape a reserved word in Oracle?

2018-12-31 20:42发布

In TSQL I could use something like Select [table] from tablename to select a column named "table".

How do I do this for reserved words in oracle?

Edit: I've tried square braces, double quotes, single quotes, and backquotes, they don't work...

As a further clarification, I have a column which someone named comment. As this is a reserved word oracle is chucking a wobbly trying to select with it, its failing when parsing the query. I've tried Select "comment" from tablename but it didn't work. I'll check case and come back.

5条回答
残风、尘缘若梦
2楼-- · 2018-12-31 21:06

Oracle normally requires double-quotes to delimit the name of identifiers in SQL statements, e.g.

SELECT "MyColumn" AS "MyColAlias"
FROM "MyTable" "Alias"
WHERE "ThisCol" = 'That Value';

However, it graciously allows omitting the double-quotes, in which case it quietly converts the identifier to uppercase:

SELECT MyColumn AS MyColAlias
FROM MyTable Alias
WHERE ThisCol = 'That Value';

gets internally converted to something like:

SELECT "ALIAS" . "MYCOLUMN" AS "MYCOLALIAS"
FROM "THEUSER" . "MYTABLE" "ALIAS"
WHERE "ALIAS" . "THISCOL" = 'That Value';
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美炸的是我
3楼-- · 2018-12-31 21:07

Oracle does use double-quotes, but you most likely need to place the object name in upper case, e.g. "TABLE". By default, if you create an object without double quotes, e.g.

CREATE TABLE table AS ...

Oracle would create the object as upper case. However, the referencing is not case sensitive unless you use double-quotes!

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墨雨无痕
4楼-- · 2018-12-31 21:21

From a quick search, Oracle appears to use double quotes (", eg "table") and apparently requires the correct case—whereas, for anyone interested, MySQL defaults to using backticks (`) except when set to use double quotes for compatibility.

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妖精总统
5楼-- · 2018-12-31 21:21

double quotes worked in oracle when I had the keyword as one of the column name.

eg:

select t."size" from table t 
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时光乱了年华
6楼-- · 2018-12-31 21:22

you have to rename the column to an other name because TABLE is reserved by Oracle.

You can see all reserved words of Oracle in the oracle view V$RESERVED_WORDS.

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