我怎么能查询,就像我想要输出一样,就像我用tbl_clinics.clinic_name对它进行分组。现在我的查询发生了什么?它为什么,它没有显示我的零值,就像我想要这样的输出:
clinic name | total_check
Clinic 1 | 4
Clinic 2 | 0
Clinic 3 | 0
Clinic 4 | 0
这是我的问题:
SELECT
tbl_clinics.clinic_name,
COALESCE(COUNT(tbl_check_up.check_up_id),0) AS total_check
FROM
tbl_clinics
LEFT OUTER JOIN tbl_check_up ON tbl_clinics.clinic_id = tbl_check_up.clinic_id
WHERE tbl_clinics.user_id = "102" AND MONTH(tbl_check_up.check_up_date) = "02"
GROUP BY tbl_clinics.clinic_name
我得到的只是这些:
clinic_name | total_check
Clinic 1 | 4
为什么它没有显示我的其他诊所? ..我怎么能操纵这些? 。请帮助我从我想要的产品中获得正确的输出,并向我解释为什么我的输出不是很好。
答案 0 :(得分:1)
WHERE子句将确定将输出哪些行。如果您希望输出表“tbl_clinics”中的所有记录,请尝试以下操作:
SELECT tbl_clinics.clinic_name,
Count(tbl_check_up.check_up_id) AS total_check
FROM tbl_clinics
LEFT JOIN tbl_check_up
ON tbl_clinics.clinic_id = tbl_check_up.clinic_id
AND tbl_clinics.user_id = "102"
AND Month(tbl_check_up.check_up_date) = "02"
GROUP BY tbl_clinics.clinic_name
另外,我认为COUNT()上的COALESCE()是不必要的,因为当没有遇到行时,COUNT()将始终返回0,而不是NULL。
答案 1 :(得分:0)
你可以尝试
<?xml version="1.0"?>
<manifest package="net.geographx.LinesGame" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="1.0" android:versionCode="10" android:installLocation="auto">
<application android:hardwareAccelerated="true" android:name="org.qtproject.qt5.android.bindings.QtApplication" android:label="@string/app_name" android:icon="@drawable/icon">
<activity android:configChanges="orientation|uiMode|screenLayout|screenSize|smallestScreenSize|layoutDirection|locale|fontScale|keyboard|keyboardHidden|navigation" android:name="org.qtproject.qt5.android.bindings.QtActivity" android:label="@string/app_name" android:screenOrientation="portrait" android:launchMode="singleTop">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
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<!-- Application arguments -->
<meta-data android:name="android.app.lib_name" android:value="LinesGameQt"/>
<meta-data android:name="android.app.qt_sources_resource_id" android:resource="@array/qt_sources"/>
<meta-data android:name="android.app.repository" android:value="default"/>
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<meta-data android:name="android.app.bundled_in_assets_resource_id" android:resource="@array/bundled_in_assets"/>
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<meta-data android:name="android.app.libs_prefix" android:value="/data/local/tmp/qt/"/>
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<meta-data android:value="@string/ministro_not_found_msg" android:name="android.app.ministro_not_found_msg"/>
<meta-data android:value="@string/ministro_needed_msg" android:name="android.app.ministro_needed_msg"/>
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<!-- Background running -->
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application still try to draw after
"applicationStateChanged(Qt::ApplicationSuspended)"
signal is sent! -->
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* minimal - useful for Quick Controls 2 apps, it is much faster than "full"
* none - useful for apps that don't use any of the above Qt modules
-->
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<!-- For adding service(s) please check: https://wiki.qt.io/AndroidServices -->
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<uses-sdk android:minSdkVersion="19" android:targetSdkVersion="23"/>
<supports-screens android:largeScreens="true" android:normalScreens="true" android:anyDensity="true" android:smallScreens="true"/>
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<uses-feature android:glEsVersion="0x00030000" android:required="true"/>
</manifest>