我有数十个与COLUMN_NAME ENTITY_ID相关的表，我想查找所有具有特定值的相关记录，我可以找到带有特定列的表格
select * from all_tab_cols a where a.COLUMN_NAME='ENTITY_ID';
而且我可以找到每个表的记录
select * from TABLENAME where ENTITY_ID='100';
是否有一种方法可以使用单个SQL查看所有表中的所有相关记录？
假设我们有一个表ACCOUNT，其中的CUST_ID列如下：
SQL> SELECT OWNER, A.TABLE_NAME, COLUMN_NAME FROM
2 ALL_TAB_COLS A
3 WHERE
4 A.COLUMN_NAME = 'CUST_ID';
OWNER TABLE_NAME COLUMN_NAME
---------- -------------------- --------------------
TEJASH ACCOUNT CUST_ID
SQL> SELECT * FROM ACCOUNT;
ACC_NR SUM_ CUST_ID
---------- ---------- ----------
500 3400 100
现在，我要搜索所有我有权访问的表，以找到所有具有CUST_ID列且值100的表。
SQL> SELECT
2 table_name, COLUMN_NAME,
3 to_number(xmlquery('/ROWSET/ROW/C/text()'
4 passing xmltype(dbms_xmlgen.getxml(
5 'select count(1) as c '
6 || 'from "' || owner || '"."' || table_name || '" WHERE ' || COLUMN_NAME || '=''100'''))
7 returning content)) as cOUNT
8 FROM ALL_TAB_COLS A
9 WHERE A.COLUMN_NAME = 'CUST_ID';
TABLE_NAME COLUMN_NAME COUNT
-------------------- -------------------- ----------
ACCOUNT CUST_ID 1
在这里，将出现具有CUST_ID列的每个表，并且COUNT列将显示具有CUST_ID = 100的表中的记录数现在，让我们在另一张表中添加一列，然后查看效果：
SQL> ALTER TABLE ACTIVE_USERS ADD CUST_ID VARCHAR2(100);
Table altered.
SQL> INSERT INTO ACTIVE_USERS VALUES (5,SYSDATE, SYSDATE, 200);
1 row created.
SQL> SELECT * FROM ACTIVE_USERS;
CUST_NUM START_DATE END_DATE CUST
---------- -------------------- -------------------- ----
########## 21-NOV-19 21-NOV-19 200
########## 21-NOV-19 21-NOV-19
########## 01-JAN-18 01-JAN-19
########## 01-JAN-18
########## 01-JAN-19 01-JUN-19
########## 01-JAN-17 01-MAR-19
6 rows selected.
现在，再次运行查询以从所有表中查找数据：
SQL> SELECT
2 table_name, COLUMN_NAME,
3 to_number(xmlquery('/ROWSET/ROW/C/text()'
4 passing xmltype(dbms_xmlgen.getxml(
5 'select count(1) as c '
6 || 'from "' || owner || '"."' || table_name || '" WHERE ' || COLUMN_NAME || '=''100'''))
7 returning content)) as cOUNT
8 FROM ALL_TAB_COLS A
9 WHERE A.COLUMN_NAME = 'CUST_ID';
TABLE_NAME COLUMN_NAME COUNT
-------------------- -------------------- ----------
ACCOUNT CUST_ID 1
ACTIVE_USERS CUST_ID 0
SQL>
而且，它起作用了！再次向
ACTIVE_USERS表中添加更多数据并查看结果。
SQL> INSERT INTO ACTIVE_USERS VALUES (6,SYSDATE-1, SYSDATE, 100);
1 row created.
SQL> INSERT INTO ACTIVE_USERS VALUES (7,SYSDATE-2, SYSDATE, 100);
1 row created.
SQL> INSERT INTO ACTIVE_USERS VALUES (8,SYSDATE-3, SYSDATE, 100);
1 row created.
SQL> SELECT * FROM ACTIVE_USERS;
CUST_NUM START_DATE END_DATE CUST
---------- -------------------- -------------------- ----
########## 21-NOV-19 21-NOV-19 200
########## 20-NOV-19 21-NOV-19 100
########## 19-NOV-19 21-NOV-19 100
########## 18-NOV-19 21-NOV-19 100
########## 21-NOV-19 21-NOV-19
########## 01-JAN-18 01-JAN-19
########## 01-JAN-18
########## 01-JAN-19 01-JUN-19
########## 01-JAN-17 01-MAR-19
9 rows selected.
让我们现在检查查询的结果。
SQL> SELECT
2 table_name, COLUMN_NAME,
3 to_number(xmlquery('/ROWSET/ROW/C/text()'
4 passing xmltype(dbms_xmlgen.getxml(
5 'select count(1) as c '
6 || 'from "' || owner || '"."' || table_name || '" WHERE ' || COLUMN_NAME || '=''100'''))
7 returning content)) as cOUNT
8 FROM ALL_TAB_COLS A
9 WHERE A.COLUMN_NAME = 'CUST_ID';
TABLE_NAME COLUMN_NAME COUNT
-------------------- -------------------- ----------
ACCOUNT CUST_ID 1
ACTIVE_USERS CUST_ID 3
SQL>
再次，它有效！ ：）干杯！