# 可能插入重复数据的 SQL 语句

 

解决方法：

1. REPLACE
2. INSERT ... ON DUPLICATE KEY

 

REPLACE [LOW_PRIORITY | DELAYED]    [INTO] tbl_name    [PARTITION (partition_name,...)]    [(col_name,...)]    {
    VALUES | VALUE} ({expr | DEFAULT},...),(...),...REPLACE [LOW_PRIORITY | DELAYED]    [INTO] tbl_name    [PARTITION (partition_name,...)]    SET col_name={expr | DEFAULT}, ...REPLACE [LOW_PRIORITY | DELAYED]    [INTO] tbl_name    [PARTITION (partition_name,...)]    [(col_name,...)]    SELECT ...

 

INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]    [INTO] tbl_name    [PARTITION (partition_name,...)]    [(col_name,...)]    {
    VALUES | VALUE} ({expr | DEFAULT},...),(...),...    [ ON DUPLICATE KEY UPDATE      col_name=expr        [, col_name=expr] ... ]INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]    [INTO] tbl_name    [PARTITION (partition_name,...)]    SET col_name={expr | DEFAULT}, ...    [ ON DUPLICATE KEY UPDATE      col_name=expr        [, col_name=expr] ... ]INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]    [INTO] tbl_name    [PARTITION (partition_name,...)]    [(col_name,...)]    SELECT ...    [ ON DUPLICATE KEY UPDATE      col_name=expr        [, col_name=expr] ... ]

 

Reference:

https://dev.mysql.com/doc/refman/5.7/en/replace.html REPLACE Syntax

https://dev.mysql.com/doc/refman/5.7/en/insert.html INSERT Syntax

 

# FULL OUTER JOIN 

 

MySQL 不支持 FULL OUTER JOIN。

 

解决方法：

左连接 + 右连接。

select * from A LEFT JOIN B on A.id = B.id unionselect *from A RIGHT JOIN B on A.id = B.id;

 

Reference:

http://www.cnblogs.com/liuyifan/p/4985512.html