使用MYSQL时，Grails条件查询失败，语法错误

Posted 2021-03-28

当应用程序连接到mysql实例时，我的查询失败。使用H2内存数据库时，查询工作正常。所有其他查询都可以使用MYSQL。

错误消息：您的SQL语法中有错误;检查与您的MySQL服务器版本对应的手册，以便在第1行的'）'附近使用正确的语法

控制器动作：

def index() {
def currentUser = currentUser()
def peopleFollowing = currentUser.following
def c = Post.createCriteria()
    def postList = c.list  {
       'in' ("user", peopleFollowing)
       'order' "dateCreated", "desc"
    }
[postList:postList, user : currentUser, peopleFollowing:peopleFollowing]
}

当我删除in子句时，查询将针对MYSQL运行。所以似乎：'in'（“用户”，peopleFolllowing）导致了这个问题。我认为问题在于它是一个MYSQL保留字。我尝试过使用反引号，但一直都会出现语法错误......？

class Post {


String content
Date dateCreated
User user


static belongsTo = [user : User]

static hasMany = [postComments: PostComment]

static constraints = {
    content (blank: false)
}

static mapping = {
    sort dateCreated:"desc"
    content type:"text"
    postComments sort:"dateCreated",  order:"desc"
}

}

class Post {String content Date dateCreated User user static belongsTo = [user：User] static hasMany = [postComments：PostComment] static constraints = {content（blank：false）} static mapping = {sort dateCreated：“desc”content type：“ text“postComments sort：”dateCreated“，order：”desc“}} class Post {String content Date dateCreated User user static belongsTo = [user：User] static hasMany = [postComments：PostComment] static constraints = {content（blank：false） ）} static mapping = {sort dateCreated：“desc”内容类型：“text”postComments sort：“dateCreated”，order：“desc”}}

答案

我通过这样做来解决问题：

def postList = Post.findAllByUserInList( peopleFollowing )

另一答案

我使用ids解决了它，并在0中添加了一个List：

def currentUser = currentUser()
def peopleFollowingIds = currentUser.following.id
peopleFollowingIds.add(0)
def c = Post.createCriteria()
def postList = c.list  {
    'in' ("user_id", peopleFollowingIds)
    'order' "dateCreated", "desc"
}

或类似的东西。