如何附加到 SQL 中的现有记录？
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How to append to a existing record in SQL?
提问by jorame
Can someone tell me how to append in SQL? I've going around all day trying to figure this out. This is what I have so far:
有人能告诉我如何在 SQL 中追加吗？我整天都在试图弄清楚这一点。这是我到目前为止：
update table1
set field1 = field1 + '123456'
where field2 = '12'
Sorry, I forgot to mention that I'm updating more than one field in the statement.
抱歉，我忘了提及我正在更新声明中的多个字段。
回答by bsexton
Your statement should work as long as field1 is not null or the data to be appended is not null.
只要 field1 不为空或要附加的数据不为空，您的语句就应该起作用。
Something like this could help in the case where field1 is null.
在 field1 为空的情况下，这样的事情可能会有所帮助。
update table1 set field1 = ISNULL(field1, '') + '123456' where field2 = '12'
回答by Randy
in Oracle, the string concatenation goes like this:
在 Oracle 中，字符串连接是这样的：
field1 = field1 || '12345'
回答by Wes
Your question is a bit confusing because you are saying append but your example is really just a set operation:
您的问题有点令人困惑，因为您说的是 append 但您的示例实际上只是一个集合操作：
update table1 set field1 = '123456', field2 = '' where field2 = '12'
if you were actually appending it would depend on your database but lookup string concatenation for reference.
如果您实际上是追加，则取决于您的数据库，但查找字符串连接以供参考。
update table set field1 = concat(field2, '3456') where field2 = '12'
回答by MikeM
here are the differences between varchar concatenation and integer addition, you appear to have varchar concatenation going on, you may need to use CAST and CONVERT (Transact-SQL)to add your numbers
这是 varchar 连接和整数加法之间的区别，您似乎正在进行 varchar 连接，您可能需要使用CAST 和 CONVERT (Transact-SQL)来添加您的数字
example 1 w/integers:
示例 1 带整数：
DECLARE @table1 TABLE(field1 int, field2 int)
INSERT INTO @table1 VALUES (123456, 12)
SELECT 'before' as 'before', * FROM @table1
UPDATE @table1 SET field1 = field1 + 123456 WHERE field2 = 12
SELECT 'after' as 'after', * FROM @table1
example 1 results:
示例 1 结果：
example 2 w/varchar:
带有 varchar 的示例 2：
DECLARE @table2 TABLE(field1 varchar(50), field2 varchar(2))
INSERT INTO @table2 VALUES ('123456', '12')
SELECT 'before' as 'before', * FROM @table2
UPDATE @table2 SET field1 = field1 + '123456' WHERE field2 = '12'
SELECT 'after' as 'after', * FROM @table2
example 2 results:
示例 2 结果：
回答by Abdulkadir Suleiman
If you are working with MySQL the query can be simplified as
如果您正在使用 MySQL，则查询可以简化为
UPDATE table set field1 = CONCAT('123456', field1) where field2 = '12'
