列表大小 return 0 来自 sqlite 查询
List size return 0 from sqlite query
我试图通过连接三个表来查询前提列表。但是，当我添加 WHERE 时，我的列表 return 为空。我试图记录所有内容……似乎没有它，我就能获得前提列表……但这是错误的。我在 DB Browser for sqlite 上尝试了 运行ning 查询，它设法 运行 和 return 正确的列表。请帮助我。
这是我的查询代码..
public List<TXN_Premise> getTxnTableData(String tableName, String columnName) {
ArrayList<TXN_Premise> itemList = new ArrayList<>();
String selectQuery = "SELECT "
+ Constants.COLUMN_PREMISE_REF + ", "
+ Constants.COLUMN_PREMISE_NAME + ", "
+ Constants.COLUMN_PREMISE_ADDRESS + ", "
+ Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_PREMISE_CATEGORY_ID + " AS " + Constants.COLUMN_FK_PREMISE_CATEGORY_ID +", "
+ Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_PREMISE_CATEGORY_MASTER_ID + " AS " + Constants.COLUMN_FK_PREMISE_CATEGORY_MASTER_ID + ", "
+ Constants.COLUMN_PREMISE_REG_NO + ", "
+ Constants.COLUMN_PREMISE_REG_DATE + ", "
+ Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_DESCRIPTION + " AS premiseCategoryDescription, "
+ Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_DESCRIPTION + " AS premiseCategoryMasterDescription "
+ " FROM " + tableName
+ " LEFT JOIN " + Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + " ON " +
Constants.TXN_PREMISE_TABLE + "." + Constants.COLUMN_FK_PREMISE_CATEGORY_MASTER_ID + " = " + Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_CODE
+ " LEFT JOIN " + Constants.REF_PREMISE_CATEGORY_TABLE + " ON " +
Constants.TXN_PREMISE_TABLE + "." + Constants.COLUMN_FK_PREMISE_CATEGORY_ID + " = " + Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_CODE
// + " WHERE " + Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS'"
// + Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS' AND "
// + Constants.COLUMN_PREMISE_NAME + " <> '-' AND " + Constants.COLUMN_PREMISE_NAME + " <> '-TIADA-'"
+ " ORDER BY " + columnName + " ASC LIMIT 3";
Log.d("test", "getTxnTableData: " + selectQuery);
try {
open();
//make sure the database is not empty
if (sqLiteDatabase != null) {
//get a cursor for all state in the database
Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, null);
Log.d("test", "getTxnTableData: cursor " + cursor.toString());
Log.d("test", "getTxnTableData: outside");
if (cursor.moveToFirst()) {
while (!cursor.isAfterLast()) {
TXN_Premise premiseColumn = new TXN_Premise();
// premiseColumn.setPremiseId(cursor.getString(0));
premiseColumn.setPremiseRef(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_REF)));
premiseColumn.setPremiseName(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_NAME)));
premiseColumn.setPremiseAddress(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_ADDRESS)));
premiseColumn.setFk_premiseCategoryId(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_FK_PREMISE_CATEGORY_ID)));
premiseColumn.setFk_premiseCategoryMasterId(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_FK_PREMISE_CATEGORY_MASTER_ID)));
premiseColumn.setPremiseRegNo(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_REG_NO)));
premiseColumn.setPremiseRegDate(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_REG_DATE)));
// todo: temp premise category description
premiseColumn.setPremiseCategoryName(cursor.getString(cursor.getColumnIndex("premiseCategoryDescription")));
premiseColumn.setPremiseCategoryMasterName(cursor.getString(cursor.getColumnIndex("premiseCategoryMasterDescription")));
Log.d("test", "getTxnTableData: premiseName " + cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_NAME)));
//add premiseColumn in the cursor
itemList.add(premiseColumn);
cursor.moveToNext();
}
}
cursor.close();
}
close();
} catch (SQLException e) {
e.printStackTrace();
}
Log.d("test", "getTxnTableData: itemlist " + itemList.size() );
return itemList;
}
不可能重现问题并因此确定问题，因为 WHERE 子句依赖于基础数据。
因此您需要遵循简单的问题确定。
正如您指出的那样，它可以在没有 WHERE 子句的情况下工作
1) 删除WHERE子句和运行。
1a) 如果您现在检索行然后逐个条件逐步构建 WHERE 子句，那将突出问题。
1b) 如果删除 WHERE 子句后没有行的问题仍然存在，则从 String selectQuery = "SELECT * FROM " + tableName; 开始逐步构建整个 SQL，检查结果是否符合预期。
我建议更改
Log.d("test", "getTxnTableData: cursor " + cursor.toString());
到
Log.d("test", "getTxnTableData: cursor " + cursor.getCount());
这将显示游标中的行数。
此外，您还可以利用
编辑
仔细观察，WHERE 子句似乎存在一些问题：-
为简化起见，将在任何地方做出以下决议：-
Constants.REF_PREMISE_CATEGORY_TABLE 似乎将被替换为 rpcConstants.REF_PREMISE_CATEGORY_MASTER_TABLE 似乎将被替换为 mrpc
Constants.COLUMN_LANG出现，将被替换为lang
Constants.COLUMN_PREMISE_NAME出现，将被替换为name
所以 :-
" WHERE " + Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS'"
+ Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS' AND "
+ Constants.COLUMN_PREMISE_NAME + " <> '-' AND " + Constants.COLUMN_PREMISE_NAME + " <> '-TIADA-'"
变为（????(n) 用于指示问题，其中 n 标识特定问题，并指出它不是 SQL 的一部分） :-
" WHERE rpc.lang = 'MYS' ????(1) mrpc.lang = 'MYS' AND name <> '-' AND name <> '-TIADA-' ????(2)
问题 1 ????(1) 两次检查之间没有条件，例如也许应该是 WHERE rpc.lang = 'MYS' AND mrpc.lang = 'MYS' .......
- 这可能会产生类似
的错误
.....
[ near "?????????": syntax error ]
Exception Name: NS_ERROR_FAILURE
Exception Message: Component returned failure code: 0x80004005 (NS_ERROR_FAILURE)
问题 2 ????(2) 这对条件将 永远 满足 name 只能是 - 或 -TIADA- 永远不能两者都是 。也许您的意思是 OR 在这种情况下，我会将它们括在括号中。
所以也许代码可以是：-
" WHERE " +
Constants.REF_PREMISE_CATEGORY_TABLE + "." +
Constants.COLUMN_LANG +
" = 'MYS'" +
" AND " +
Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." +
Constants.COLUMN_LANG + " = 'MYS' " +
" AND (" +
Constants.COLUMN_PREMISE_NAME + " <> '-' " +
" OR " +
Constants.COLUMN_PREMISE_NAME + " <> '-TIADA-'" +
")"
我试图通过连接三个表来查询前提列表。但是，当我添加 WHERE 时，我的列表 return 为空。我试图记录所有内容……似乎没有它，我就能获得前提列表……但这是错误的。我在 DB Browser for sqlite 上尝试了 运行ning 查询，它设法 运行 和 return 正确的列表。请帮助我。
这是我的查询代码..
public List<TXN_Premise> getTxnTableData(String tableName, String columnName) {
ArrayList<TXN_Premise> itemList = new ArrayList<>();
String selectQuery = "SELECT "
+ Constants.COLUMN_PREMISE_REF + ", "
+ Constants.COLUMN_PREMISE_NAME + ", "
+ Constants.COLUMN_PREMISE_ADDRESS + ", "
+ Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_PREMISE_CATEGORY_ID + " AS " + Constants.COLUMN_FK_PREMISE_CATEGORY_ID +", "
+ Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_PREMISE_CATEGORY_MASTER_ID + " AS " + Constants.COLUMN_FK_PREMISE_CATEGORY_MASTER_ID + ", "
+ Constants.COLUMN_PREMISE_REG_NO + ", "
+ Constants.COLUMN_PREMISE_REG_DATE + ", "
+ Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_DESCRIPTION + " AS premiseCategoryDescription, "
+ Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_DESCRIPTION + " AS premiseCategoryMasterDescription "
+ " FROM " + tableName
+ " LEFT JOIN " + Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + " ON " +
Constants.TXN_PREMISE_TABLE + "." + Constants.COLUMN_FK_PREMISE_CATEGORY_MASTER_ID + " = " + Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_CODE
+ " LEFT JOIN " + Constants.REF_PREMISE_CATEGORY_TABLE + " ON " +
Constants.TXN_PREMISE_TABLE + "." + Constants.COLUMN_FK_PREMISE_CATEGORY_ID + " = " + Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_CODE
// + " WHERE " + Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS'"
// + Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS' AND "
// + Constants.COLUMN_PREMISE_NAME + " <> '-' AND " + Constants.COLUMN_PREMISE_NAME + " <> '-TIADA-'"
+ " ORDER BY " + columnName + " ASC LIMIT 3";
Log.d("test", "getTxnTableData: " + selectQuery);
try {
open();
//make sure the database is not empty
if (sqLiteDatabase != null) {
//get a cursor for all state in the database
Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, null);
Log.d("test", "getTxnTableData: cursor " + cursor.toString());
Log.d("test", "getTxnTableData: outside");
if (cursor.moveToFirst()) {
while (!cursor.isAfterLast()) {
TXN_Premise premiseColumn = new TXN_Premise();
// premiseColumn.setPremiseId(cursor.getString(0));
premiseColumn.setPremiseRef(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_REF)));
premiseColumn.setPremiseName(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_NAME)));
premiseColumn.setPremiseAddress(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_ADDRESS)));
premiseColumn.setFk_premiseCategoryId(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_FK_PREMISE_CATEGORY_ID)));
premiseColumn.setFk_premiseCategoryMasterId(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_FK_PREMISE_CATEGORY_MASTER_ID)));
premiseColumn.setPremiseRegNo(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_REG_NO)));
premiseColumn.setPremiseRegDate(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_REG_DATE)));
// todo: temp premise category description
premiseColumn.setPremiseCategoryName(cursor.getString(cursor.getColumnIndex("premiseCategoryDescription")));
premiseColumn.setPremiseCategoryMasterName(cursor.getString(cursor.getColumnIndex("premiseCategoryMasterDescription")));
Log.d("test", "getTxnTableData: premiseName " + cursor.getString(cursor.getColumnIndex(Constants.COLUMN_PREMISE_NAME)));
//add premiseColumn in the cursor
itemList.add(premiseColumn);
cursor.moveToNext();
}
}
cursor.close();
}
close();
} catch (SQLException e) {
e.printStackTrace();
}
Log.d("test", "getTxnTableData: itemlist " + itemList.size() );
return itemList;
}
不可能重现问题并因此确定问题，因为 WHERE 子句依赖于基础数据。
因此您需要遵循简单的问题确定。
正如您指出的那样，它可以在没有 WHERE 子句的情况下工作
1) 删除WHERE子句和运行。
1a) 如果您现在检索行然后逐个条件逐步构建 WHERE 子句，那将突出问题。
1b) 如果删除 WHERE 子句后没有行的问题仍然存在，则从
String selectQuery = "SELECT * FROM " + tableName;开始逐步构建整个 SQL，检查结果是否符合预期。
我建议更改
Log.d("test", "getTxnTableData: cursor " + cursor.toString());
到
Log.d("test", "getTxnTableData: cursor " + cursor.getCount());
这将显示游标中的行数。
此外，您还可以利用
编辑
仔细观察，WHERE 子句似乎存在一些问题：-
为简化起见，将在任何地方做出以下决议：-
Constants.REF_PREMISE_CATEGORY_TABLE似乎将被替换为rpcConstants.REF_PREMISE_CATEGORY_MASTER_TABLE似乎将被替换为mrpcConstants.COLUMN_LANG出现，将被替换为langConstants.COLUMN_PREMISE_NAME出现，将被替换为name
所以 :-
" WHERE " + Constants.REF_PREMISE_CATEGORY_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS'"
+ Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." + Constants.COLUMN_LANG + " = 'MYS' AND "
+ Constants.COLUMN_PREMISE_NAME + " <> '-' AND " + Constants.COLUMN_PREMISE_NAME + " <> '-TIADA-'"
变为（????(n) 用于指示问题，其中 n 标识特定问题，并指出它不是 SQL 的一部分） :-
" WHERE rpc.lang = 'MYS' ????(1) mrpc.lang = 'MYS' AND name <> '-' AND name <> '-TIADA-' ????(2)
问题 1
????(1)两次检查之间没有条件，例如也许应该是WHERE rpc.lang = 'MYS'ANDmrpc.lang = 'MYS' .......- 这可能会产生类似 的错误
..... [ near "?????????": syntax error ] Exception Name: NS_ERROR_FAILURE Exception Message: Component returned failure code: 0x80004005 (NS_ERROR_FAILURE)
问题 2
????(2)这对条件将 永远 满足 name 只能是 - 或 -TIADA- 永远不能两者都是 。也许您的意思是OR在这种情况下，我会将它们括在括号中。
所以也许代码可以是：-
" WHERE " +
Constants.REF_PREMISE_CATEGORY_TABLE + "." +
Constants.COLUMN_LANG +
" = 'MYS'" +
" AND " +
Constants.REF_PREMISE_CATEGORY_MASTER_TABLE + "." +
Constants.COLUMN_LANG + " = 'MYS' " +
" AND (" +
Constants.COLUMN_PREMISE_NAME + " <> '-' " +
" OR " +
Constants.COLUMN_PREMISE_NAME + " <> '-TIADA-'" +
")"