在MySQL中将字符串与字段值连接

问题描述：

我需要在MySQL查询中将一个字符串与一个字段值连接起来，以便左联接两个表.

I have the need to concatenate a string with a field value in a MySQL query in order to LEFT JOIN two tables.

表1中有一列名为"category_id"的数字，例如61、78、94等.

Table one has a column called "category_id" with numeric values, such as 61, 78, 94 and such.

表2中有一列查询"，它表示请求路由机制，其值包括"product_id = 68"，"category_id = 74"，"manufacturer_id = 99"等等.

Table two has a column called "query" which refers to a request route mechanism, and it has values such as "product_id=68", "category_id=74", "manufacturer_id=99" and so on.

因此，在我的查询中，只要从设置字符串派生的串联字符串和"category_id"列的值与查询字段匹配，我就需要连接表.

So in my query I require to join the tables when ever a concatenated string derived from a set string and the value of the "category_id" column matches the query field.

我的SQL语句当前为:

My SQL statement is currently:

SELECT * FROM tableOne 
LEFT JOIN tableTwo
ON tableTwo.query = 'category_id=' + tableOne.category_id

我尝试使用||运算符而不是+运算符，但仍然没有运气.是否有可能在MySQL中执行此操作，或者我已经在这里开枪了?

I have tried using the || operator instead of the + operator, but still no luck. Is it possible to do this in MySQL, or have I jumped the gun here?

答

您是否尝试过使用

Have you tried using the concat() function?

ON tableTwo.query = concat('category_id=',tableOne.category_id)

在MySQL中将字符串与字段值连接

相关推荐