下面的查询方式是否正确？union前的括号该怎么实现？

[jiyang7]

The language of WCDB

Swift

The version of WCDB

v2.0.4

The platform of WCDB

iOS

The installation of WCDB

Cocoapods

What's the issue?

我在一个do catch内查询同一个表中两个不同条件的数据，发现结果1 result 和 结果2 otherResult 数据相同，理论上两个条件不同结果是不应该相同的，如果分开至两个do catch执行两次查询结果则不同。

    do {
        let condition = PCNotificationMessageInfo.Properties.notifyType.in([6, 7, 10])
        let select = try messageNoticeDB.prepareSelect(of: MessageNoticeTableType.messageInfo.tableType, fromTable: MessageNoticeTableType.messageInfo.rawValue).where(condition).limit(40)
        var result = try select.allObjects(of: PCNotificationMessageInfo.self)
        resultArray.append(contentsOf: result)

        let otherSelect = try messageNoticeDB.prepareSelect(of: MessageNoticeTableType.messageInfo.tableType, fromTable: MessageNoticeTableType.messageInfo.rawValue).where(!condition)
        let otherResult = try otherSelect.allObjects(of: PCNotificationMessageInfo.self)
        resultArray.append(contentsOf: otherResult)
    } catch {

    }

尝试使用union发现无法使用括号 let statementSelect = StatementSelect().select(properties).from(tableName).where(condition).limit(40).union().select(properties).from(tableName).where(!condition)

请问如下语句该如何实现 (SELECT FROM tableName WHERE condition1 LIMIT 40) union (SELECT FROM tableName WHERE condition2)

[Qiuwen-chen]

StatementSelect().select(Column.all()).from("tableName1").where(condition1).union().select(Column.all()).from("tableName2").where(condition2)

[jiyang7]

请问 LIMIT 40是否添加 如果按回复添加 StatementSelect().select(Column.all()).from("tableName1").where(condition1).limit(40).union().select(Column.all()).from("tableName2").where(condition2)

通过输出 description 发现语句是，总数限制40，并非单条语句限制40条 SELECT FROM tableName1 WHERE condition1 union SELECT FROM tableName2 WHERE condition2 LIMIT 40 并非 (SELECT FROM tableName1 WHERE condition1 LIMIT 40) union (SELECT FROM tableName2 WHERE condition2)

[Qiuwen-chen]

SQLite's select syntax can only put limit at the end of the statement: https://www.sqlite.org/lang_select.html

[Qiuwen-chen]

May be you should use two queries.

[jiyang7]

麻烦看下第一个问题

我在一个do catch内查询同一个表中两个不同条件的数据，发现结果1 result 和 结果2 otherResult 数据相同，理论上两个条件不同结果是不应该相同的，如果分开至两个do catch执行两次查询结果则不同。

do {
    let condition = PCNotificationMessageInfo.Properties.notifyType.in([6, 7, 10])
    let select = try messageNoticeDB.prepareSelect(of: MessageNoticeTableType.messageInfo.tableType, fromTable: MessageNoticeTableType.messageInfo.rawValue).where(condition).limit(40)
    var result = try select.allObjects(of: PCNotificationMessageInfo.self)
    resultArray.append(contentsOf: result)

    let otherSelect = try messageNoticeDB.prepareSelect(of: MessageNoticeTableType.messageInfo.tableType, fromTable: MessageNoticeTableType.messageInfo.rawValue).where(!condition)
    let otherResult = try otherSelect.allObjects(of: PCNotificationMessageInfo.self)
    resultArray.append(contentsOf: otherResult)
} catch {

}

请问这个问题有原因么?issues/wiki是否有相关内容？

[Qiuwen-chen]

You can give a demo project to reproduce it.

[jiyang7]

简单建了一个测试工程，麻烦看一下。

https://github.com/jiyang7/WCDBTestSample.git

点击“SelectWrongTestData”按钮，“selectWrongTestData”方法中，“result”和“otherResult”的个数为什么相同？？？即使不加limit限制，“result”和“otherResult”的个数也会相同，这显然是不正确的。

[Qiuwen-chen]

Got it, it is indeed an obvious bug. I will fix it in the next version.

For now, you can use this interface to avoid this problem: database.getObjects(on: Sample.Properties.all, fromTable: tableName, where: condition, orderBy: [orderBy])

[Qiuwen-chen]

Fixed in v2.1.6