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Mybatis trim tag how to use, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain in detail for you, people with this need can come to learn, I hope you can gain something.

The following are the attributes involved in the trim tag:

Here are a few examples to illustrate the use of trim tags.

1. Use trim tags to remove redundant and keywords

There is an example of this:

SELECT * FROM BLOG

WHERE

State = # {state}

If >

AND title like # {title}

If >

AND author_name like # {author.name}

If >

Select >

What happens if none of these conditions match? Eventually the SQL will look like this:

SELECT * FROM BLOG

WHERE

This causes the query to fail. What if only the second condition matches? The SQL will end up like this:

SELECT * FROM BLOG

WHERE

AND title like 'someTitle'

You can use the where tag to solve this problem, and the where element inserts the "WHERE" clause only if the condition of at least one child element returns the SQL clause. Also, if the statement begins with "AND" or "OR", the where element removes them.

SELECT * FROM BLOG

State = # {state}

If >

AND title like # {title}

If >

AND author_name like # {author.name}

If >

Where >

Select >

Trim tags can also perform the same function, written as follows:

State = # {state}

If >

AND title like # {title}

If >

AND author_name like # {author.name}

If >

Trim >

2. Use trim tags to remove extra commas

There are the following examples:

If the conditions in the red box do not match, the sql statement will look like this:

INSERT INTO role (role_name,) VALUES (roleName,)

The insert will fail. Using the trim tag can solve this problem with only a few modifications, as shown below:

One of the most important attributes is

SuffixOverrides= ","

Means to remove the extra comma at the end of the sql statement

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