SQL MS Access 中的 CONCAT 等效项
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/20403870/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
CONCAT equivalent in MS Access
提问by salty
I'm doing some work in MS Access and I need to append a prefix to a bunch of fields, I know SQL but it doesn't quite seem to work the same in Access
我正在 MS Access 中做一些工作，我需要在一堆字段中附加一个前缀，我知道 SQL，但它在 Access 中似乎不太一样
Basically I need this translated to a command that will work in access:
基本上，我需要将其转换为可用于访问的命令：
UPDATE myTable
SET [My Column] = CONCAT ("Prefix ", [My Column])
WHERE [Different Column]='someValue';
I've searched up and down and can't seem to find a simple translation.
我上下搜索，似乎找不到简单的翻译。
回答by HansUp
There are two concatenation operators available in Access: +; and &. They differ in how they deal with Null.
Access 中有两个连接运算符：+; 和&。它们在处理 Null 的方式上有所不同。
"foo" + Nullreturns Null
"foo" + Null返回空
"foo" & Nullreturns "foo"
"foo" & Null返回 "foo"
So if you want to update Null [My Column]fields to contain "Prefix "afterwards, use ...
因此，如果您想更新 Null[My Column]字段以在"Prefix "之后包含，请使用 ...
SET [My Column] = "Prefix " & [My Column]
But if you prefer to leave it as Null, you could use the +operator instead ...
但是，如果您希望将其保留为 Null，则可以改用+运算符...
SET [My Column] = "Prefix " + [My Column]
However, in the second case, you could revise the WHEREclause to ignore rows where [My Column]contains Null.
但是，在第二种情况下，您可以修改WHERE子句以忽略[My Column]包含 Null 的行。
WHERE [Different Column]='someValue' AND [My Column] Is Not Null
回答by Fred
UPDATE myTable
SET [My Column] = "Prefix " & [My Column]
WHERE [Different Column]='someValue';
As far as I am aware there is no CONCAT
据我所知，没有 CONCAT
回答by Gordon Linoff
You can use the &operator:
您可以使用&运算符：
UPDATE myTable
SET [My Column] = "Prefix " & [My Column]
WHERE [Different Column]='someValue';
回答by Kiril Rusev
Since there is no Concat function in MS-ACCESS, you can simply combine both strings with +operator:
由于 MS-ACCESS 中没有 Concat 函数，您可以简单地将两个字符串与+运算符组合起来：
UPDATE myTable
SET [My Column] = "Prefix " + [My Column]
WHERE [Different Column]='someValue';
