从CSV文件加载数据，其中doublequote用作转义字符 [英] LOAD DATA from CSV file where doublequote was used as the escape character
问题描述
我有一堆CSV数据，我需要加载到MySQL数据库。好吧，CSV-ish，也许。 （编辑：实际上，它看起来像RFC 4180中描述的东西）
每一行都是逗号分隔的双引号字符串列表。要转义出现在列值中的任何双引号，请使用双精度双引号。反斜杠可以代表自己。
例如，行：
，\wave\，hello，牧师说，什么是恐吓报价
如果解析成JSON应为：
[，\\wave\\，\hello，\牧师，什么是\scare-quotes \\good for？，I'm reading \Bossypants\]
我试图使用 LOAD DATA 来读取CSV，但我遇到了一些奇怪的行为。
例如，假设我有一个简单的两列表：
shell％mysql exampledb -edescribe person
+ ------- + ----------- + ------ + ----- + - -------- + ------- +
|字段|类型| Null |键|默认|额外|
+ ------- + --- -------- + ------ + ----- + --------- + ------- +
| ID | int（11） ）| YES | | NULL | |
| UID | char（255）| YES | | NULL | |
+ ------- + ----------- + ------ + ----- + --------- + - ----- +
shell％
如果我的第一个非标题行输入文件结束于：
shell％cat temp-1 .csv
ID，UID
9，
0，Steve the Pirate
1，\Alpha
2，HobanWashWashburne
3，Pastor Veal
4，Tucker
10 b $ b5，Simon
6，Sonny
7，Wat\
我可以加载每个非标题行，但第一个：
mysql>删除从人;
查询OK，0行受影响（0.00秒）
mysql> LOAD DATA
LOCAL INFILE'temp-1.csv'
INTO TABLE person
FIELDS
TERMINATED BY'，'
ENCLOSED BY''
ESCAPED BY''
LINES
终止于'\\\
'
IGNORE 1 LINES
;
Query OK，9 rows affected（0.00 sec）
Records：9 Deleted：0 Skipped：0 Warnings：0
mysql> SELECT * FROM person;
+ ------ + ------------------------ +
| ID | UID |
+ ------ + ------------------------ +
| 0 |史蒂夫海盗|
| 10 | |
| 1 | \Alpha |
| 2 | HobanWashWashburne |
| 3 |牧师小牛|
| 4 | Tucker |
| 5 |西蒙|
| 6 | Sonny |
| 7 | Wat\ |
+ ------ + ------------------------ +
集合中的9行（0.00秒）
或者我可以加载包括标题的所有行：
mysql>删除从人;
查询OK，9行受影响（0.00秒）
mysql> LOAD DATA
LOCAL INFILE'temp-1.csv'
INTO TABLE person
FIELDS
TERMINATED BY'，'
ENCLOSED BY''
ESCAPED BY''
LINES
终止于'\\\
'
IGNORE 0 LINES
;
查询OK，11行受影响，1警告（0.01秒）
记录：11删除：0跳过：0警告：1
mysql>显示警告;
+ --------- + ------ + ---------------------------- ---------------------------- +
|级别|代码|消息|
+ --------- + ------ + ---------------------------- ---------------------------- +
|警告| 1366 |整数值不正确：第1行的ID列为ID
+ --------- + ------ + ---------------------------- ---------------------------- +
集合中的1行（0.00秒）
mysql> ; SELECT * FROM person;
+ ------ + ------------------------ +
| ID | UID |
+ ------ + ------------------------ +
| 0 | UID |
| 9 | |
| 0 |史蒂夫海盗|
| 10 | |
| 1 | \Alpha |
| 2 | HobanWashWashburne |
| 3 |牧师小牛|
| 4 | Tucker |
| 5 |西蒙|
| 6 | Sonny |
| 7 | Wat\ |
+ ------ + ------------------------ +
集合中的11行（0.00秒）
如果我的输入文件的任何行都不在：
shell％cat temp-2.csv
ID，UID
0，Steve the Pirate
1，\Alpha
2，HobanWashWashburne
3，Pastor Veal
4，Tucker
5，Simon
6，Sonny
7，Wat\\ b 那么我可以不加载行：
mysql>删除从人;
查询OK，11行受影响（0.00秒）
mysql> LOAD DATA
LOCAL INFILE'temp-2.csv'
INTO TABLE person
FIELDS
TERMINATED BY'，'
ENCLOSED BY''
ESCAPED BY''
LINES
终止于'\\\
'
IGNORE 1 LINES
;
查询OK，0行受影响（0.00秒）
记录：0已删除：0已跳过：0警告：0
mysql> SELECT * FROM person;
空集（0.00秒）
或者我可以加载包括标题的所有行：
mysql>删除从人;
查询OK，0行受影响（0.00秒）
mysql> LOAD DATA
LOCAL INFILE'temp-2.csv'
INTO TABLE person
FIELDS
TERMINATED BY'，'
ENCLOSED BY''
ESCAPED BY''
LINES
终止于'\\\
'
IGNORE 0 LINES
;
Query OK，9 rows affected，1 warning（0.03 sec）
Records：9 Deleted：0 Skipped：0 Warnings：1
mysql>显示警告;
+ --------- + ------ + ---------------------------- ---------------------------- +
|级别|代码|消息|
+ --------- + ------ + ---------------------------- ---------------------------- +
|警告| 1366 |整数值不正确：第1行的ID列为ID
+ --------- + ------ + ---------------------------- ---------------------------- +
集合中的1行（0.00秒）
mysql> ; SELECT * FROM person;
+ ------ + ------------------------ +
| ID | UID |
+ ------ + ------------------------ +
| 0 | UID |
| 0 |史蒂夫海盗|
| 1 | \Alpha |
| 2 | HobanWashWashburne |
| 3 |牧师小牛|
| 4 | Tucker |
| 5 |西蒙|
| 6 | Sonny |
| 7 | Wat\ |
+ ------ + ------------------------ +
集合中的9行（0.00秒）
现在我发现了很多办法做错了，我如何使用<$ c $
根据
a href =http://dev.mysql.com/doc/refman/5.0/en/load-data.html =noreferrer> LOAD DATA ，将双重双引号视为双引号是默认值：
如果字段以ENCLOSED BY字符，该字符的实例只有在后跟字段或行TERMINATED BY序列时才被识别为终止字段值。为了避免歧义，字段值中的ENCLOSED BY字符的出现可以加倍，并且被解释为字符的单个实例。例如，如果指定ENCLOSED BY''，引号将按如下所示处理：
BIG boss - >BIG老板
BIG老板 - >BIG老板
BIG老板 - >BIG b $ b
所以我需要做的是禁用解释 c>
<$ p>使用 $ p> LOAD DATA
LOCAL INFILE'temp-1.csv'
INTO TABLE person
FIELDS
TERMINATED BY'，'
BY''
ESCAPED BY''
LINES
TERMINATED BY'\\\
'
IGNORE 1 LINES
;
I have a bunch of CSV data that I need to load into a MySQL database. Well, CSV-ish, perhaps. (edit: actually, it looks like the stuff described in RFC 4180)
Each row is a list of comma-separated doublequoted strings. To escape any doublequotes that appear within a column value, double doublequotes are used. Backslashes are allowed to represent themselves.
For example, the line:
"", "\wave\", ""hello,"" said the vicar", "what are ""scare-quotes"" good for?", "I'm reading ""Bossypants"""
if parsed into JSON should be:
[ "", "\\wave\\", "\"hello,\" said the vicar", "what are \"scare-quotes\" good for?", "I'm reading \"Bossypants\"" ]
I'm trying to use the LOAD DATA to read the CSV in, but I'm running into some weird behaviour.
As an example, consider if I have a simple two column table
shell% mysql exampledb -e "describe person"
+-------+-----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+---------+-------+
| ID | int(11) | YES | | NULL | |
| UID | char(255) | YES | | NULL | |
+-------+-----------+------+-----+---------+-------+
shell%
If the first non-header line of my input file ends on "":
shell% cat temp-1.csv
"ID","UID"
"9",""
"0","Steve the Pirate"
"1","\Alpha"
"2","Hoban ""Wash"" Washburne"
"3","Pastor Veal"
"4","Tucker"
"10",""
"5","Simon"
"6","Sonny"
"7","Wat\"
I can either load every non-header line but the first:
mysql> DELETE FROM person;
Query OK, 0 rows affected (0.00 sec)
mysql> LOAD DATA
LOCAL INFILE 'temp-1.csv'
INTO TABLE person
FIELDS
TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY '"'
LINES
TERMINATED BY '\n'
IGNORE 1 LINES
;
Query OK, 9 rows affected (0.00 sec)
Records: 9 Deleted: 0 Skipped: 0 Warnings: 0
mysql> SELECT * FROM person;
+------+------------------------+
| ID | UID |
+------+------------------------+
| 0 | Steve the Pirate |
| 10 | |
| 1 | \Alpha |
| 2 | Hoban "Wash" Washburne |
| 3 | Pastor Veal |
| 4 | Tucker |
| 5 | Simon |
| 6 | Sonny |
| 7 | Wat\ |
+------+------------------------+
9 rows in set (0.00 sec)
Or I can load all lines including the header:
mysql> DELETE FROM person;
Query OK, 9 rows affected (0.00 sec)
mysql> LOAD DATA
LOCAL INFILE 'temp-1.csv'
INTO TABLE person
FIELDS
TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY '"'
LINES
TERMINATED BY '\n'
IGNORE 0 LINES
;
Query OK, 11 rows affected, 1 warning (0.01 sec)
Records: 11 Deleted: 0 Skipped: 0 Warnings: 1
mysql> show warnings;
+---------+------+--------------------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------------------+
| Warning | 1366 | Incorrect integer value: 'ID' for column 'ID' at row 1 |
+---------+------+--------------------------------------------------------+
1 row in set (0.00 sec)
mysql> SELECT * FROM person;
+------+------------------------+
| ID | UID |
+------+------------------------+
| 0 | UID |
| 9 | |
| 0 | Steve the Pirate |
| 10 | |
| 1 | \Alpha |
| 2 | Hoban "Wash" Washburne |
| 3 | Pastor Veal |
| 4 | Tucker |
| 5 | Simon |
| 6 | Sonny |
| 7 | Wat\ |
+------+------------------------+
11 rows in set (0.00 sec)
If no lines of my input file end on "":
shell% cat temp-2.csv
"ID","UID"
"0","Steve the Pirate"
"1","\Alpha"
"2","Hoban ""Wash"" Washburne"
"3","Pastor Veal"
"4","Tucker"
"5","Simon"
"6","Sonny"
"7","Wat\"
then I can either load no lines:
mysql> DELETE FROM person;
Query OK, 11 rows affected (0.00 sec)
mysql> LOAD DATA
LOCAL INFILE 'temp-2.csv'
INTO TABLE person
FIELDS
TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY '"'
LINES
TERMINATED BY '\n'
IGNORE 1 LINES
;
Query OK, 0 rows affected (0.00 sec)
Records: 0 Deleted: 0 Skipped: 0 Warnings: 0
mysql> SELECT * FROM person;
Empty set (0.00 sec)
Or I can load all the lines including the header:
mysql> DELETE FROM person;
Query OK, 0 rows affected (0.00 sec)
mysql> LOAD DATA
LOCAL INFILE 'temp-2.csv'
INTO TABLE person
FIELDS
TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY '"'
LINES
TERMINATED BY '\n'
IGNORE 0 LINES
;
Query OK, 9 rows affected, 1 warning (0.03 sec)
Records: 9 Deleted: 0 Skipped: 0 Warnings: 1
mysql> show warnings;
+---------+------+--------------------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------------------+
| Warning | 1366 | Incorrect integer value: 'ID' for column 'ID' at row 1 |
+---------+------+--------------------------------------------------------+
1 row in set (0.00 sec)
mysql> SELECT * FROM person;
+------+------------------------+
| ID | UID |
+------+------------------------+
| 0 | UID |
| 0 | Steve the Pirate |
| 1 | \Alpha |
| 2 | Hoban "Wash" Washburne |
| 3 | Pastor Veal |
| 4 | Tucker |
| 5 | Simon |
| 6 | Sonny |
| 7 | Wat\ |
+------+------------------------+
9 rows in set (0.00 sec)
So now that I've discovered many ways to do it wrong, how can I use LOAD DATA to import the data from these files into my database?
解决方案 According to the documentation for LOAD DATA, treating doubled double quotes as a double quote is the default:
If the field begins with the ENCLOSED BY character, instances of that character are recognized as terminating a field value only if followed by the field or line TERMINATED BY sequence. To avoid ambiguity, occurrences of the ENCLOSED BY character within a field value can be doubled and are interpreted as a single instance of the character. For example, if ENCLOSED BY '"' is specified, quotation marks are handled as shown here:
"The ""BIG"" boss" -> The "BIG" boss
The "BIG" boss -> The "BIG" boss
The ""BIG"" boss -> The ""BIG"" boss
So all I need to do is disable interpreting \ as an escape character, by using ESCAPED BY ''.
LOAD DATA
LOCAL INFILE 'temp-1.csv'
INTO TABLE person
FIELDS
TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY ''
LINES
TERMINATED BY '\n'
IGNORE 1 LINES
;
这篇关于从CSV文件加载数据，其中doublequote用作转义字符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
