load data
參考文檔：
https://dev.mysql.com/doc/refman/8.0/en/load-data.html
LOAD DATA
[LOW_PRIORITY | CONCURRENT] [LOCAL]
INFILE 'file_name'
[REPLACE | IGNORE]
INTO TABLE tbl_name
[PARTITION (partition_name [, partition_name] ...)]
[CHARACTER SET charset_name]
[{FIELDS | COLUMNS}
[TERMINATED BY 'string']
[[OPTIONALLY] ENCLOSED BY 'char']
[ESCAPED BY 'char']
]
[LINES
[STARTING BY 'string']
[TERMINATED BY 'string']
]
[IGNORE number {LINES | ROWS}]
[(col_name_or_user_var
[, col_name_or_user_var] ...)]
[SET col_name={expr | DEFAULT}
[, col_name={expr | DEFAULT}] ...]
這一堆參數還不少。
LOCAL:是否導入本地電腦文本文件，
導入本地電腦文件：一定要啟用 local_infile 參數，否則會報錯。
導入非本地電腦文件：用戶一定要 FILE 權限，secure_file_priv參數值如果不為空，則文件一定要在這個目錄中，如果為空，則該文件只需服務器可讀。
小插曲，我本地使用mysql8.0。23客戶端，在一切條件符合的情況下，LOAD DATA數據報錯. mysql> load data local infile '/Users/1.csv' into table ceshi.t1 ; ERROR 2068 (HY000): LOAD DATA LOCAL INFILE file request rejected due to restrictions on access. 排錯一圈，才發現踩了mysql8的一個bug， https://bugs.mysql.com/bug.php?id=91872 解決方法： 在client端配置文件中加入 [client] loose-local-infile = 1 或者在使用mysql命令行時，指定 loose-local-infile = 1 連接數據庫 mysql --local-infile=1 -uroot -p123456 -P3306 -h1.1.1.1
[REPLACE | IGNORE]：如遇到唯一沖突重復處理機制
REPLACE：覆蓋寫。
IGNORE：忽略。
如果沒有指定REPLACE， IGNORE或者LOCAL，當發生錯誤時，會報錯，並且文本余下部分不會被執行。
示例： mysql> load data infile '/root/1.csv' into table ceshi.t1 ; ERROR 1265 (01000): Data truncated for column 'id' at row 2 提示：如果要在加載數據中忽略外鍵約束，需要在Load data 數據之前執行SET foreign_key_checks = 0
如果沒有指定 FIELDS 或 LINES 子句，則默認值如下
FIELDS TERMINATED BY '\t' ENCLOSED BY '' ESCAPED BY '\\'
LINES TERMINATED BY '\n' STARTING BY ''
提示：在 WINDOWS 系統中，想要正確的讀文件需要配置 LINES TERMINATED BY '\r\n'，因為WINDOWS系統通常使用兩個字符做為終止符。
CHARACTER SET charset_name
設置導入內容的字符集,默認采用character_set_database系統變量值字符集導入內容。
提示：
這里我踩了一個坑，我本地使用CRT連接數據庫，不知為何客戶端字符集是latain1了，文本中包含中文，如果以默認方式導入會出現亂碼。一般情況下，不需要指定CHARACTER SET
示例： root# cat 1.csv 1,chai 2,測試 mysql> show variables like '%character%' -> ; +--------------------------+------------------------------------+ | Variable_name | Value | +--------------------------+------------------------------------+ | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | utf8 | | character_set_filesystem | binary | | character_set_results | latin1 | | character_set_server | utf8 | | character_set_system | utf8 | | character_sets_dir | /usr/local/mysql57/share/charsets/ | +--------------------------+------------------------------------+ 8 rows in set (0.07 sec) mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '' ESCAPED BY '\\'; Query OK, 2 rows affected (0.15 sec) Records: 2 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+------+ | id | name | +----+------+ | 1 | chai | | 2 | ?? | +----+------+ 2 rows in set (0.06 sec) set names utf8; 再查詢就正常了 mysql> select * from t1; +----+----------------+ | id | name | +----+----------------+ | 1 | chai | | 2 | 測試 |
FIELDS TERMINATED BY：指定兩列之間分隔符，默認是\t ，也就是跳格，但大多時候生成的文本文件都是','逗號，所以在導入數據時，需要顯式指定。
示例： root# cat 1.csv 1,chai 2,測試 mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ','; Query OK, 2 rows affected (0.20 sec) Records: 2 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+--------+ | id | name | +----+--------+ | 1 | chai | | 2 | 測試 | +----+--------+ 2 rows in set (0.09 sec)
ENCLOSED BY：去掉字符串中包裹的符號
示例： root #cat 1.csv 1,chai 2,測試 3,""chayicha" 4,"chayige" 如果以之前的參數導入，則結果如下,里邊的引號也會寫入進去。 mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ','; Query OK, 4 rows affected (0.16 sec) Records: 4 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+-------------+ | id | name | +----+-------------+ | 1 | chai | | 2 | 測試 | | 3 | ""chayicha" | | 4 | "chayige" | +----+-------------+ 4 rows in set (0.05 sec) ##加入 ENCLOSED BY '"' 參數后，在導入時字符左右兩則的雙引號被刪掉了。 mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"'; Query OK, 4 rows affected (0.13 sec) Records: 4 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+-----------+ | id | name | +----+-----------+ | 1 | chai | | 2 | 測試 | | 3 | "chayicha | | 4 | chayige | +----+-----------+
ESCAPED BY:設置轉義字符，默認為\ 。
示例： root#cat 1.csv 1,chai 2,測試 3,"\tchayicha" 4,wo\\a\\b\\c\tchayige mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\'; Query OK, 4 rows affected (0.13 sec) Records: 4 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+------------------+ | id | name | +----+------------------+ | 1 | chai | | 2 | 測試 | | 3 | chayicha | | 4 | wo\a\b\c chayige | +----+------------------+
LINES STARTING BY：忽略一個公共前綴,如示例，只有以 cha 開頭的記錄正確寫入到了數據庫，這個參數應該不常用
示例： root#cat 1.csv cha1,chai 2,測試 cha3,"yicha" 4,chayige mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\' LINES STARTING BY 'cha'; Query OK, 3 rows affected, 2 warnings (0.14 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 2 mysql> select * from t1; +----+-------+ | id | name | +----+-------+ | 1 | chai | | 3 | yicha | | 0 | NULL | +----+-------+
LINES TERMINATED BY 'string'：分行符，一般情況下遇到回行即分行 (\r\n)
示例： 演示一次遇到句號(。)即換行符 root#cat 2.csv a,chai。2,測試。3,chayicha。 mysql> load data local infile '/Users/2.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\' LINES TERMINATED BY '。'; Query OK, 4 rows affected, 4 warnings (0.15 sec) Records: 4 Deleted: 0 Skipped: 0 Warnings: 4 mysql> select * from t1; +----+----------+ | id | name | +----+----------+ | 0 | chai | | 2 | 測試 | | 3 | chayicha | | 0 | NULL | +----+----------+ 4 rows in set (0.07 sec)
IGNORE number {LINES | ROWS}:跳過開始的多少行才進行導入，如果文本中有字段名，可以跳過第一行.
示例： root# cat 1.csv 1,chai 2,測試 3,"yicha" 4,chayige mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\' IGNORE 1 LINES; Query OK, 3 rows affected (0.13 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+---------+ | id | name | +----+---------+ | 2 | 測試 | | 3 | yicha | | 4 | chayige | +----+---------+
[(col_name_or_user_var [, col_name_or_user_var] ...)]:手動指定要插入的列
示例： root# cat 1.csv 1,chai 2,測試 3,"yicha" 4,chayige mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\' IGNORE 1 LINES(id,name); Query OK, 3 rows affected (0.16 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+---------+------+ | id | name | age | +----+---------+------+ | 2 | 測試 | NULL | | 3 | yicha | NULL | | 4 | chayige | NULL | +----+---------+------+ 3 rows in set (0.09 sec)
[SET col_name={expr | DEFAULT} [, col_name={expr | DEFAULT}] ...]:在加載數據時做一些計算或更新一些其它字段值。
示例： root# cat 1.csv 1,chai 2,測試 3,"yicha" 4,chayige #在寫入數據時，更新age字段列 mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\' IGNORE -> 1 LINES(id,name) set age=10; Query OK, 3 rows affected (0.13 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+---------+------+ | id | name | age | +----+---------+------+ | 2 | 測試 | 10 | | 3 | yicha | 10 | | 4 | chayige | 10 | +----+---------+------+ 3 rows in set (0.07 sec) #在寫入數據時對數據做二次邏輯處理 mysql> load data local infile '/Users/1.csv' into table ceshi.t1 FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '\\' IGNORE -> 1 LINES(id,@name) set name=concat(@name,1); Query OK, 3 rows affected (0.14 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 0 mysql> select * from t1; +----+----------+------+ | id | name | age | +----+----------+------+ | 2 | 測試1 | NULL | | 3 | yicha1 | NULL | | 4 | chayige1 | NULL | +----+----------+------+ 3 rows in set (0.07 sec)