Question

我有如下所示的oracle sql查询，我只想提取一个与t2 table匹配的名称。我正在使用查询获取记录，但由于我在t1中有超过4000万个名称而花了很多时间t2表中有0.02万张。

col1的t1数据：

N Wind Pudding Dr
Hasty Pudding Ln
Banana Pudding on the Go
Saint Barbaras R C Church
St Barbaras Rd

col1的t2数据：

Pudding
Barbaras

查询：

select t2.col1,t1.col1
from t1, t2
where t1.col1 like '% t2.col1 %';

输出为：

Pudding       N Wind Pudding Dr
Barbaras      Saint Barbaras R C Church

Answer 1

未经测试：

select t2.col1,
       (select t1.col1 from t1
        where t1.col1 like '%' || t2.col1 || '%''
        fetch first 1 row only)
from t2

也许不是最有效的方法...

Answer 2

还有一些选项用于选择与t1列值匹配的 any t2表行。

一个：

SQL> select max(t1.col), t2.col
  2  from t1 join t2 on instr(t1.col, t2.col) > 0
  3  group by t2.col;

MAX(T1.COL)                              COL
---------------------------------------- ----------
St Barbaras Rd                           Barbaras
N Wind Pudding Dr                        Pudding

两个：

SQL> select t1_col, t2_col
  2  from (select t1.col t1_col,
  3               t2.col t2_col,
  4               row_number() over (partition by t2.col order by null) rn
  5        from t1 join t2 on instr(t1.col, t2.col) > 0
  6       )
  7  where rn = 1;

T1_COL                                   T2_COL
---------------------------------------- ----------
Saint Barbaras R C Church                Barbaras
N Wind Pudding Dr                        Pudding

SQL>

Answer 3

尝试使用CONTEXT索引

CREATE INDEX text_indx  ON t1(col1) INDEXTYPE IS CTXSYS.CTXCAT;

SELECT t2.col1,t1.col1
  FROM t1, t2
 WHERE CONTAINS(t1.col1, t2.col1) > 0;

使用like联接2个表并仅获取第一条记录

3 个答案: