sqlite 计算子查询标识的表的行数

Question

我想获取 Sqlite3 数据库中每个表的行数。我想避免写出手写查询。我可以得到这样的表列表：

SELECT name FROM sqlite_master WHERE type='table'

我想在这样的子查询中使用它：

select count (*) from (SELECT name FROM sqlite_master WHERE type='table');

但只会返回子查询中的总行数，这不是我想要的。

如何编写一个查询来列出每个表及其计数？

我见过 dynamic SQL 这种东西，但我认为 SQLite 没有。

我已经编写了一个 bash 循环来执行此操作，但我更愿意将其作为单个查询来完成

for t in $(sqlite3 data.db "SELECT name FROM sqlite_master WHERE type='table'"); do
  echo -n "$t = "; sqlite3 data.db "SELECT COUNT(*) FROM $t;"
done

想法赞赏

Answer 1

我使用以下 shell 语法盲目地从我正在调试的数据库中的表中获取计数。

db="database.db"
for i in `sqlite3 "$db" "SELECT name FROM sqlite_master WHERE 
type='table';"`; do echo -n $i\ \=\ ; sqlite3 "$db" "SELECT 
COUNT(*) FROM $i;"; done

cols = 0
sqlite_sequence = 0
datacols = 17
hits = 0
host = 0
document = 0
admin = 2
comments = 0

Answer 2

如果您想了解这些值以进行调试，请查看 sqlite3_analyzer 工具的输出。

如果您想在程序中使用这些值，则必须在程序中动态生成查询。

Answer 3

我希望下面的代码能够完整地用于某些人。

我用C#.net编程语言编写了示例代码，Nuget包是Microsoft.Data.Sqlite，版本为7.0.10

代码：

internal class Program
{
  static void Main(string[] args)
  {        
    string dbMainQuery = $" WITH x(i) AS (select name from \"main\".sqlite_master WHERE type='table') \r\n SELECT PRINTF('SELECT count(*) as NumberOfRow FROM %s;',i) as QueryInfo,i as Tablename FROM x ;";
    DataTable dtMain = new DataTable();
    DataTable dtTableCountInfo = new DataTable();
    dtTableCountInfo.Columns.Add("Id", typeof(string));
    dtTableCountInfo.Columns.Add("TableName", typeof(string));
    dtTableCountInfo.Columns.Add("TotalCount", typeof(string));
    //Get the sqlite all db data
    using (SqliteConnection sqliteConnection = new SqliteConnection("Data Source=dataStoreage.db;Pooling=True;"))
    {
        sqliteConnection.Open();
        using var transaction = sqliteConnection.BeginTransaction(IsolationLevel.ReadCommitted);
        try
        {
            using SqliteCommand sqliteCommand = new SqliteCommand(dbMainQuery, sqliteConnection, transaction);
            var dataReader = sqliteCommand.ExecuteReader(CommandBehavior.Default);
            dtMain.Load(dataReader);

            // Itration on the each table and get the row numbers
            if (dtMain.Rows.Count > 0)
            {
                for (int i = 0; i < dtMain.Rows.Count; i++)
                {
                    var rowInfo = dtTableCountInfo.NewRow();
                    using SqliteCommand countInfoCmd = new SqliteCommand(dtMain.Rows[i][0].ToString(), sqliteConnection, transaction);
                    rowInfo["Id"] = i + 1;
                    rowInfo["TableName"] = dtMain.Rows[i][1].ToString();
                    rowInfo["TotalCount"] = countInfoCmd.ExecuteScalar();

                    dtTableCountInfo.Rows.Add(rowInfo);
                }
            }
            transaction.Commit();
            // TO DO : do the conversion of the data table as per your needs
        }
        catch (Exception e)
        {
            transaction.RollbackAsync();
        }
    }
    Console.ReadLine();
  }
}

和模型类：

public class TableSummryReport
{
    public string Id { get; set; }
    public string TableName { get; set; }
    public string TotalCount { get; set; }
}