在PostgreSQL中有一种更快的方法来基本上在几行中执行if吗？
说我有一张桌子
ticket | row | archived
1 | 1 | true
1 | 2 | true
1 | 3 | true
2 | 1 | false
2 | 2 | true
有没有什么方法可以在ticket =的列下面做一个if语句？因此,ticket = 1的地方是真的
true && true && true = true
并且ticket = 2将是假的,因为
false && true = false
或者我应该坚持下去
SELECT ( (SELECT COUNT(*) FROM table WHERE ticket = 1)
= (SELECT COUNT(*) FROM table WHERE ticket = 1 AND archived = true) )
昨天我试图从统计表中过滤掉用户ID时遇到了Postgres中的一个奇怪问题.当我们这样做,例如user_id != 24,Postgres的排除其中的行user_id是NULL也.
我创建了以下测试代码,显示相同的结果.
CREATE TEMPORARY TABLE test1 (
id int DEFAULT NULL
);
INSERT INTO test1 (id) VALUES (1), (2), (3), (4), (5), (2), (4), (6),
(4), (7), (5), (9), (5), (3), (6), (4), (3), (7),
(NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL);
SELECT COUNT(*) FROM test1;
SELECT id, COUNT(*) as count
FROM test1
GROUP BY id;
SELECT id, COUNT(*) as count
FROM test1
WHERE id != 1
GROUP BY id;
SELECT id, …尝试在两台不同的Ubuntu计算机上运行Android Studio 2.2.3时,我一直收到此错误.一个运行14.04 Trusty,另一个运行16.04 Xenial.
它运行启动屏幕,加载栏到达结束,然后它就坐在那里,这个错误显示在控制台中.
OpenJDK 64-Bit Server VM warning: ignoring option MaxPermSize=350m; support was removed in 8.0
Looking in classpath from com.intellij.util.lang.UrlClassLoader@2077d4de for /com/sun/jna/linux-x86-64/libjnidispatch.so
Found library resource at jar:file:/home/me/Downloads/android-studio/lib/jna.jar!/com/sun/jna/linux-x86-64/libjnidispatch.so
Trying /home/me/.AndroidStudio2.2/system/tmp/jna3820816485682346846.tmp
Found jnidispatch at /home/me/.AndroidStudio2.2/system/tmp/jna3820816485682346846.tmp
[ 9485] WARN - dea.updater.SdkComponentSource - File /home/me/.android/repositories.cfg could not be loaded.
[ 9618] WARN - s.RepoProgressIndicatorAdapter - File /home/me/.android/repositories.cfg could not be loaded.
[ 9994] ERROR - llij.ide.plugins.PluginManager - java.lang.ClassCastException: sun.font.CompositeFont cannot be cast to sun.font.PhysicalFont
java.lang.RuntimeException: java.lang.ClassCastException: sun.font.CompositeFont cannot be cast …