In the SQL statement in the MyBatis query, be sure to determine the condition of NULL

Not rigorous writing, may be error: in (), this situation does not conform to the MySQL syntax.

Select from Loanwhere loan_id in

<foreach item= "item" index= "id" collection= "list" open= "(" separator= "," close= ")" >

#{item}

Either in a MyBatis SQL file or in a Java program.

the syntax in SQL :

<select id= "Findbyloanids" parametertype= "List" >

SELECT *

From p2p_loan_variation where 1 = 1

<if test= "List! = null and list.size>0" >

and loan_id in

<foreach item= "item" index= "id" collection= "list" open= "("

Separator= "," close= ")" >

#{item}

</foreach>

</if>

<if test= "List==null or list.size==0" >and 1=0</if>

</select>

What to do in Java:

list<loanvariation> list = null;

if (Listutils.isnotempty (loadids) {

List =loanvariationdao.findbyloanids (loanids);

}

return list;

If there are multiple Java methods calling DAO Mapper, it is easier to write in SQL, after all, only one "parameter check" is required.

The above wording is for a query condition, if there are multiple query conditions, remember to deal with the relationship between the conditions,

such as a=1 and B =2 or c=3.

If there is an in condition, it is best to add parentheses, (a=1) and (b =2) or (c in ...).

In the SQL statement in the MyBatis query, be sure to determine the condition of NULL