假設單一陳述式中的 VALUES 子句通常包含幾列,則 VALUES 中的 INSERT 幾乎一律不會平行化。 INGEST 指令類似。 在背景中,此指令會以具有 VALUES 陳述式的多個個別 INSERT 傳送,且不可能在資料庫分割區內平行化。 即使從一般來源表格大量 INSERT ,Db2可能也不知道要從來源子查詢產生多少列。Db2最佳化工具會決定 IN...
GENERATED ALWAYSとして定義された列では、OVERRIDING USER VALUE句により、 Db2 はユーザー指定の値を無視し、代わりに値を生成します。 例えば、 DSN8C10.EMP_PHOTO_RESUMEの行を、同様の定義を持つ別のテーブルにコピーしたいと仮定します(両方のテーブルにROWID列がGENERATED ALWAYSとして定義さ...
+——+ | 1 | | 2 | | 3 | | 4 | | 5 | +——+ 5 rows in set (0.00 sec) 批注:这时因为没有设置快照读,所以当session 2有数据更新时,可查到该数据,接下来我们继续在session 2 插入数据 session 2: mysql> insert into xx values (6); Query OK, 1 row affected (0.00 sec)这时再观察...
avoid insertion of duplicate entries in a BULK INSERT statement Bad performance of EXCEPT operator Basic - select with fixed values - invert columns to rows Basic CTE query, get full path of something recursive BCP Error - Copy direction must be either 'in', 'out' or 'format'. BCP Export...
Adding query parameter to NpgsqlCommand results in Exception Adding row into existing CSV file using C# adding rows to datatable displayed in datagridview Adding SqlParameter in in List, having a value from TryParse Adding this project as a reference would cause a circular dependency. adding valu...
with (\n" + " 'x' = 'y', \n" + " 'asd' = 'data'\n" + ")\n"; tenv.executeSql(sql); } static void testCreateTableWithUserDefinedType(StreamTableEnvironment tenv) { final String sql = "create table t(\n" + " a catalog1.db1.MyType1,\n" + " b db2.MyType2\n" +...
INSERTinserts new rows into an existing table. TheINSERT ... VALUESform of the statement inserts rows based on explicitly specified values. TheINSERT ... SELECTform inserts rows selected from another table or tables. TheINSERT ... VALUESform with multiple value lists is supported in MySQL Versi...
SetOutputIdentity is useful when BulkInsert is done to multiple related tables, that have Identity column. After Insert is done to first table, we need Id-s that were generated in Db because they are FK(ForeignKey) in second table. It is implemented with OUTPUT as part of MERGE Query, so...
特征基本特点支持下列的数据库 MS SQL Server MS SQL Server 4.0 MS SQL Azure MS Access Oracle MySQL SQLite PostgreSQL IBM DB2 Sybase使用: 创建连接: public static IDbContext QueryDB() { return new DbContext().ConnectionStringName("testDBContext", DbProviderTypes.SqlServer); } config中的连接字符...
(字段1,字段2,字段3 …) values (值1,值2,值3 …)" sql="insert into 目标数据表 select * from 源数据表" (把源数据表的记录添加到目标数据表) (5) 数据记录统计函数: AVG(字段名) 得出一个表格栏平均值 COUNT(*|字段名) 对数据行数的统计或对某一栏有值的数据行数统计 MAX(字段名) 取得一个...