Ios 通过FMDB将数组传递给sqlite WHERE IN子句?
是否可以通过FMDB将数组传递给SELECT…WHERE…IN语句? 我试着像这样内爆阵列:Ios 通过FMDB将数组传递给sqlite WHERE IN子句?,ios,sqlite,fmdb,where-in,Ios,Sqlite,Fmdb,Where In,是否可以通过FMDB将数组传递给SELECT…WHERE…IN语句? 我试着像这样内爆阵列: NSArray *mergeIds; // An array with NSNumber Objects NSString *mergeIdString = [mergeIds componentsJoinedByString:@","]; NSString *query = @"SELECT * FROM items WHERE last_merge_id IN (?)"; FMResultSet
NSArray *mergeIds; // An array with NSNumber Objects
NSString *mergeIdString = [mergeIds componentsJoinedByString:@","];
NSString *query = @"SELECT * FROM items WHERE last_merge_id IN (?)";
FMResultSet *result = [database executeQuery:query, mergeIdString];
这仅在数组中只有一个对象时有效,这使我相信FMDB会在整个内爆字符串周围添加引号
因此,我尝试按原样将数组传递给FMDB的方法:
NSArray *mergeIds; // An array with NSNumber Objects
NSString *query = @"SELECT * FROM items WHERE last_merge_id IN (?)";
FMResultSet *result = [database executeQuery:query, mergeIds];
这根本不起作用
我在自述文件或FMDB的github页面上的示例中没有找到任何关于它的内容
谢谢,Stefan我想我必须使用
executeQueryWithFormat
(根据FMDB文档,这不是推荐的方法)。无论如何,我的解决方案是:
NSArray *mergeIds; // An array of NSNumber Objects
NSString *mergeIdString = [mergeIds componentsJoinedByString:@","];
NSString *query = @"SELECT * FROM items WHERE last_merge_id IN (?)";
FMResultSet *res = [self.database executeQueryWithFormat:query, mergeIdString];
如果键是字符串,我将使用以下代码生成SQL命令: (假设strArray是包含NSString元素的NSArray)
请注意:如果strArray中的任何元素可能包含“双引号”符号,则您需要编写额外的代码(在这两行之前),通过编写两个双引号来对其进行转义。我也遇到了同样的问题,我已经解决了,至少在我自己的应用程序中。首先,像这样构造查询,将问号的数量与数组中的数据量相匹配:
NSString *getDataSql = @"SELECT * FROM data WHERE dataID IN (?, ?, ?)";
然后使用executeQuery:withArgumentsInArray
调用:
FMResultSet *results = [database executeQuery:getDataSql withArgumentsInArray:dataIDs];
在我的例子中,NSArray中有一个名为DataID的NSString对象数组。我尝试了各种方法来让这个SQL查询工作,最后通过SQL/函数调用的组合,我得到了正确的结果。再加上Wayne Liu,如果您知道字符串不包含单引号或双引号,您可以简单地执行:
NSString * delimitedString = [strArray componentsJoinedByString:@"','"];
NSString * sql = [NSString stringWithFormat:@"SELECT * FROM tableName WHERE fieldName IN ('%@')", delimitedString];
这里是FMDatabase的Swift扩展,它将数组查询参数分解为多个命名参数
extension FMDatabase {
func executeQuery(query: String, params:[String: AnyObject]) -> FMResultSet? {
var q = query
var d = [String: AnyObject]()
for (key, val) in params {
if let arr = val as? [AnyObject] {
var r = [String]()
for var i = 0; i < arr.count; i++ {
let keyWithIndex = "\(key)_\(i)"
r.append(":\(keyWithIndex)")
d[keyWithIndex] = arr[i]
}
let replacement = ",".join(r)
q = q.stringByReplacingOccurrencesOfString(":\(key)", withString: "(\(replacement))", options: NSStringCompareOptions.LiteralSearch, range: nil)
}
else {
d[key] = val
}
}
return executeQuery(q, withParameterDictionary: d)
}
}
我创建了一个简单的FMDB扩展来解决这个问题:
但是,当对象是NSStrings而不是NSNumbers时,这仍然不起作用:-(这不起作用。SQL清理将把它看作一个变量。
extension FMDatabase {
func executeQuery(query: String, params:[String: AnyObject]) -> FMResultSet? {
var q = query
var d = [String: AnyObject]()
for (key, val) in params {
if let arr = val as? [AnyObject] {
var r = [String]()
for var i = 0; i < arr.count; i++ {
let keyWithIndex = "\(key)_\(i)"
r.append(":\(keyWithIndex)")
d[keyWithIndex] = arr[i]
}
let replacement = ",".join(r)
q = q.stringByReplacingOccurrencesOfString(":\(key)", withString: "(\(replacement))", options: NSStringCompareOptions.LiteralSearch, range: nil)
}
else {
d[key] = val
}
}
return executeQuery(q, withParameterDictionary: d)
}
}
let sql = "SELECT * FROM things WHERE id IN :thing_ids"
let rs = db.executQuery(sql, params: ["thing_ids": [1, 2, 3]])