Question

SQLiteDatabase中的query方法里的各个参数是干什么的

Answer 1

您好。

DB_TABLENAME ----  数据库表名

String数组    ----  表中数据字段名

privacy=1    ----   查询where语句

下面是官方说明文件：

public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)
 
Since: API Level 1
Query the given table, returning a Cursor over the result set.
Parameters
 
table    The table name to compile the query against.
columns    A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
selection    A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
selectionArgs    You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
groupBy    A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
having    A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
orderBy    How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
limit    Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.
Returns
 
A Cursor object, which is positioned before the first entry. Note that Cursors are not synchronized, see the documentation for more details.

Answer 2

table
The table name to compile the query against.(要查询的表名.)

columns
A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.(想要显示的列，若为空则返回所有列，不建议设置为空，如果不是返回所有列)

selection
A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.(where子句，声明要返回的行的要求，如果为空则返回表的所有行。)

selectionArgs
You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.( where子句对应的条件值)

groupBy
A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.(分组方式，若为空则不分组.)

having
A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.(having条件，若为空则返回全部（不建议）)

orderBy
How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.(排序方式，为空则为默认排序方式)

limit
Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.(限制返回的记录的条数，为空则不限制)