比较2长行Oracle Sql

Question

我有两个表格说A和B（表B是A的前一个备份表）。它们都有相同的列，其中的一列（在两个表中）都是LONG数据类型。

Columns : ID and RECORD 

我想比较两个表（可能会或可能不会有相同的ID），其结果应提供：

1. 同ID但不同RECORD和，
2. 同RECORD但不同ID 。

Answer 1

在使用long之前，必须了解一些关于LONG的事实。

使用长值是受到以下限制：

1 A table can contain only one LONG column. 
2 You cannot create an object type with a LONG attribute. 
3 LONG columns cannot appear in WHERE clauses or in integrity constraints (except that they can appear in NULL and NOT NULL constraints). 
4 LONG columns cannot be indexed. 
5 LONG data cannot be specified in regular expressions. 
6 A stored function cannot return a LONG value. 
7 You can declare a variable or argument of a PL/SQL program unit using the LONG data type. However, you cannot then call the program unit from SQL. 
8 Within a single SQL statement, all LONG columns, updated tables, and locked tables must be located on the same database. 
9 LONG and LONG RAW columns cannot be used in distributed SQL statements and cannot be replicated. 
10 If a table has both LONG and LOB columns, then you cannot bind more than 4000 bytes of data to both the LONG and LOB columns in the same SQL statement. However, you can bind more than 4000 bytes of data to either the LONG or the LOB column. 

IN ADDITION, LONG COLUMNS CANNOT APPEAR IN THESE PARTS OF SQL STATEMENTS: 

1 GROUP BY clauses, ORDER BY clauses, or CONNECT BY clauses or with the DISTINCT operator in SELECT statements 
2 The UNIQUE operator of a SELECT statement 
3 The column list of a CREATE CLUSTER statement 
4 The CLUSTER clause of a CREATE MATERIALIZED VIEW statement 
5 SQL built-in functions, expressions, or conditions 
6 SELECT lists of queries containing GROUP BY clauses 
7 SELECT lists of subqueries or queries combined by the UNION, INTERSECT, or MINUS set operators 
8 SELECT lists of CREATE TABLE ... AS SELECT statements 
9 ALTER TABLE ... MOVE statements 
10 SELECT lists in subqueries in INSERT statements 

变通方法为你做任何对比的是创建具有长柱为CLOB的景色，做任何操作。在下面检查。

create table B(ID number, RECRD long) 

create table A(ID number, RECRD long) 

select recrd from A where recrd = '12345' 

--This will throw error "illegal use of LONG datatype 

WORK AROUND : 

SQL> CREATE TABLE A_view 
    AS 
    SELECT id, 
      TO_LOB(recrd) AS recrd 
    FROM A; 


SQL> CREATE TABLE B_view 
    AS 
    SELECT id, 
      TO_LOB(recrd) AS recrd 
    FROM B; 


select * from A_view where DBMS_LOB.substr(recrd) = '12345' 


drop table a; 

drop table b; 

drop table a_view; 

drop table b_view;