We have 2 tables as shown below:
Table A:
ROWNUM
description
1
{"to": "+1111", "from": "9999"}
2
{"to": "+5555", "from": "8888"}
Table B:
COL1
COL2
+1111
222
+5555
666
Please help me with an Oracle query which replaces part of the description column present in Table A from above table.
The numbers present after text "to:" i.e., +1111 and +5555 of Table A (description column)should be compared with COL1 of Table B and replace with corresponding COL2 value.
For example : replace +1111 with 222 in Table A
replace +5555 with 666 in Table A
Table A should look like this post running of the query.
Table A:
ROWNUM
description
1
{"to": "222", "from": "9999"}
2
{"to": "666", "from": "8888"}
Thanks in advance :)
You can use techniques dedicated to JSON within a PL/SQL code values such as
DECLARE
v_jsoncol tableA.description%TYPE;
v_json_obj json_object_t;
v_new_jsoncol tableA.description%TYPE;
v_col1 tableB.col1%TYPE;
v_col2 VARCHAR2(25);
l_key_list json_key_list;
BEGIN
FOR c IN
(
SELECT *
FROM tableA
)
LOOP
v_json_obj := TREAT(json_element_t.parse(c.description) AS json_object_t);
l_key_list := v_json_obj.get_keys;
FOR i IN 1 .. l_key_list.COUNT
LOOP
IF l_key_list (i) = 'to' THEN
v_col1 := v_json_obj.get_string (l_key_list (i));
SELECT TO_CHAR(col2)
INTO v_col2
FROM tableB
WHERE col1 = v_col1;
v_json_obj.put(l_key_list (i),v_col2);
v_new_jsoncol := v_json_obj.to_string;
UPDATE tableA SET description = v_new_jsoncol WHERE row_num = c.row_num;
END IF;
END LOOP;
END LOOP;
END;
/
Demo
I used instr to get 3rd and 4th " chars position to get the value inside and replace it with other query .
Note : ROWNUM , description is reserved keywords, so i advise not to use them as column names
here is the final code:
SELECT ROWNUM ,
REPLACE (description ,
SUBSTR( description , INSTR(description, '"', 1, 3)+1,
INSTR(description, '"', 1, 4) - INSTR(description, '"', 1, 3)-1) ,
(select COL2 from tblB where COL1 =
SUBSTR( description , INSTR(description, '"', 1, 3)+1,
INSTR(description, '"', 1, 4) - INSTR(description, '"', 1, 3)-1)
)
)
from tblA
Don't use string functions for this. You should use JSON functions and can use JSON_MERGEPATCH:
MERGE INTO table_a dst
USING (
SELECT a.ROWID AS rid,
b.col2
FROM table_a a
INNER JOIN table_b b
ON JSON_VALUE(a.description, '$.to' RETURNING VARCHAR2(10)) = b.col1
) src
ON (dst.ROWID = src.RID)
WHEN MATCHED THEN
UPDATE
SET description = JSON_MERGEPATCH(
dst.description,
JSON_OBJECT(KEY 'to' VALUE src.col2)
);
Which, for your sample data:
CREATE TABLE Table_A (description CLOB CHECK (description IS JSON));
INSERT INTO table_a (description)
SELECT '{"to": "+1111", "from": "9999"}' FROM DUAL UNION ALL
SELECT '{"to": "+5555", "from": "8888"}' FROM DUAL;
CREATE TABLE Table_B (COL1, COL2) AS
SELECT '+1111', 222 FROM DUAL UNION ALL
SELECT '+5555', 666 FROM DUAL;
Then:
SELECT * FROM table_a;
Outputs:
DESCRIPTION
{"to":222,"from":"9999"}
{"to":666,"from":"8888"}
db<>fiddle here
Related
For example, I have a table with these values:
ID
Date
Col1
Col2
Col3
Col4
1
01/11/2021
A
A
B
2
01/11/2021
B
B
The A and B values are dynamic, they can be other characters as well.
Now I need somehow to get to the result that id 1 has 2 occurences of A and one of B. Id 2 has 0 occurences of A and 2 occurences of B.
I'm using dynamic SQL to do this:
for v_record in table_cursor
loop
for i in 1 .. 4
loop
v_query := 'select col'||i||' from table where id = '||v_record.id;
execute immediate v_query into v_char;
if v_char = "any letter I'm checking" then
amount := amount + 1;
end if;
end loop;
-- do somehting with the amount
end loop;
But there has to be a better much more efficient way to do this.
I don't have that much knowledge of plsql and I really don't know how to formulate this question in google. I've looked into pivot, but I don't think that will help me out in this case.
I'd appreciate it if someone could help me out.
Assuming the number of columns would be fixed at four, you could use a union aggregation approach here:
WITH cte AS (
SELECT ID, Col1 AS val FROM yourTable UNION ALL
SELECT ID, Col2 FROM yourTable UNION ALL
SELECT ID, Col3 FROM yourTable UNION ALL
SELECT ID, Col4 FROM yourTable
)
SELECT
t1.ID,
t2.val,
COUNT(c.ID) AS cnt
FROM (SELECT DISTINCT ID FROM yourTable) t1
CROSS JOIN (SELECT DISTINCT val FROM cte) t2
LEFT JOIN cte c
ON c.ID = t1.ID AND
c.val = t2.val
WHERE
t2.val IS NOT NULL
GROUP BY
t1.ID,
t2.val;
This produces:
Demo
As the title says, I am looking for a way to remove all rows from TableA where there is a matching row in TableB.
the Tables A & B have about 30 columns in them so a WHERE A.col1 = B.col1 etc would be a little problematical. Ideally I was hoping for something like
DELETE FROM tableA WHERE IN TableB
(overly simplified by this type of thing)
IN clause can compare all columns returned from select
DELETE FROM tableA WHERE ( col1,col2,col3,.. ) IN ( select col1,col2,col3... FROM TableB );
The brute force way to establish if two records from each table are the same is to just compare every column:
DELETE
FROM tableA a
WHERE EXISTS (SELECT 1 FROM tableB b WHERE a.col1 = b.col1 AND a.col2 = b.col2 AND ...
a.col30 = b.col30);
You could create function which checks structures of tables and, if they are the same, creates string containing correct conditions to compare.
For example here are two tables:
create table t1 (id, name, age) as (
select 1, 'Tom', 67 from dual union all
select 2, 'Tia', 42 from dual union all
select 3, 'Bob', 16 from dual );
create table t2 (id, name, age) as (
select 1, 'Tom', 51 from dual union all
select 3, 'Bob', 16 from dual );
Now use function:
select generate_condition('T1', 'T2') from dual;
result:
T1.ID = T2.ID and T1.NAME = T2.NAME and T1.AGE = T2.AGE
Copy this, paste and run delete query:
delete from t1 where exists (select 1 from t2 where <<PASTE_HERE>>)
Here is the function, adjust it if needed. I used user_tab_columns so if tables are on different schemas you need all_tab_columns and compare owners too. If you have Oracle 11g you can replace loop with listagg(). Second table has to contain all columns of first table and they have to be same type and length.
create or replace function generate_condition(i_t1 in varchar2, i_t2 in varchar2)
return varchar2 is
v varchar2(1000) := '';
begin
for rec in (select column_name, u2.column_id
from user_tab_cols u1
left join (select * from user_tab_cols where table_name = i_t2) u2
using (column_name, data_type, data_length)
where u1.table_name = i_t1 order by u1.column_id)
loop
if rec.column_id is null then
v := 'ERR: incompatible structures';
goto end_loop;
end if;
v := v||' and '||i_t1||'.'||rec.column_name
||' = '||i_t2||'.'||rec.column_name;
end loop;
<< end_loop >>
return(ltrim(v, ' and '));
end;
If you want to avoid running process manually you need dynamic PL/SQL.
create table tableA (a NUMBER, b VARCHAR2(5), c INTEGER);
create table tableB (a NUMBER, b VARCHAR2(5), c INTEGER);
As you said
WHERE A.col1 = B.col1 etc would be a little problematical
you could intersect the tables and mention all columns from tableA one time, like this:
delete tableA
where (a,b,c) in (select * from tableA
intersect
select * from tableB);
Have to compare the data differences between the below two tables. I have achieved this by writing a MINUS query but that does not fit for current assignment. Because few tables have 50- 60 columns and each time have to mention the columns before execution.
I have followed Expert's response and not succeeded in achieving the goal. Basically I want to write a procedure which:
Accepts both table names as parameters.
Fetch all the columns of CustomerTable.
Then MINUS query between CustomerTable and StagingCustTable only with the columns fetched in step-2.
Logging any differences.
CustomerTable
Custromer_Number
Address
order_Number
Contact
Country
Post_Code
Amount
StagingCustTable
Custromer_Number
Address
order_Number
Contact
Country
Post_Code
Amount
Run_Id
Record_Id
I would not use a procedure but a query to generate a final query.
Kind of dynamic SQL.
Simple example - let say we have the following tables and data in them:
CREATE TABLE CustomerTable(
Custromer_Number int,
Address varchar2(100),
order_Number int,
Contact int,
Country varchar2(10),
Post_Code varchar2(10),
Amount number
);
INSERT ALL
INTO CustomerTable VALUES (1, 'aaa', 1, 1, 'AA', '111', 111.11 )
INTO CustomerTable VALUES (2, 'bbb', 2, 2, 'BB', '222', 222.22 )
SELECT 1 FROM dual;
CREATE TABLE StagingCustTable
AS SELECT t.*, 1 As run_id, 1 as record_id
FROM CustomerTable t
WHERE 1=0;
INSERT ALL
INTO StagingCustTable VALUES (1, 'aaa', 1, 1, 'AA', '111', 111.11, 1, 1 )
INTO StagingCustTable VALUES (3, 'ccc', 3, 3, 'CC', '333', 333.33, 3, 3 )
SELECT 1 FROM dual;
commit;
Now when you run this simple query:
SELECT 'SELECT ' || listagg( column_name, ',' ) WITHIN GROUP ( ORDER BY column_id )
|| chr(10) || ' FROM ' || max( table_name )
|| chr(10) || ' MINUS '
|| chr(10) || 'SELECT ' || listagg( column_name, ',' ) WITHIN GROUP ( ORDER BY column_id )
|| chr(10) || ' FROM StagingCustTable ' as MySql
FROM user_tab_columns
WHERE table_name = upper( 'CustomerTable' );
you will get the following result:
MYSQL
-------------------------------------------------------------------------
SELECT CUSTROMER_NUMBER,ADDRESS,ORDER_NUMBER,CONTACT,COUNTRY,POST_CODE,AMOUNT
FROM CUSTOMERTABLE
MINUS
SELECT CUSTROMER_NUMBER,ADDRESS,ORDER_NUMBER,CONTACT,COUNTRY,POST_CODE,AMOUNT
FROM StagingCustTable
Now just copy the above query, paste it to your SQL client, run it - and the task is done in a few minutes.
I want to match Col1 from Table a to colum1 from table B.
A B
123 123-ab
234 234-bc
3443 3443-dd
However, value in table b has concatenated data. I want to match only the characters until before special character occurs(-).
I tried this : substr(table1.a,1,3) = substr(table2.b,1,3)
But this doesn’t work as some values have 4 digits.
use join and substr
select * from table_a
inner join table_b on table_a.col_a = substr(table_b.col_b, 1, length(table_a.col_a);
Using REGEXP_SUBSTR() to match on one or more numbers from the beginning of the string up to but not including the first hyphen:
SQL> with a(col1) as (
select '123' from dual union
select '234' from dual union
select '3443' from dual
),
b(col1) as (
select '123-ab' from dual union
select '234-bc' from dual union
select '3443-dd' from dual
)
select a.col1, b.col1
from a, b
where a.col1 = regexp_substr(b.col1, '^(\d+)-', 1, 1, NULL, 1);
COL1 COL1
---- -------
123 123-ab
234 234-bc
3443 3443-dd
SQL>
I am trying to use REGEXP_SUBSTR to update a column in a table and I am getting the error, missing expression.
UPDATE p_table SET f_name = SELECT REGEXP_SUBSTR ( (SELECT user_name
FROM user_info
WHERE ROWID = R_ID ('user_info')), '[^ ]{1,15}', 1, 1)
FROM DUAL;
When I add parentheses before the first select and after dual it works but sets all the rows in that column to the same value. I do not need them all to be unique but I cannot have them all the same. Thanks for any advice you could give me.
UPDATE p_table SET f_name = (SELECT REGEXP_SUBSTR ( (SELECT user_name
FROM user_info
WHERE ROWID = R_ID ('user_info')), '[^ ]{1,15}', 1, 1)
FROM DUAL);
As mentioned in #PatrickMarchand comment Oracle optimizes query, so your function called only once. AskTom article makes it clear.
To get a workaround you must introduce something linked to p_table rows into function parameters to force Oracle call it for every row.
For example rowid from p_table:
UPDATE p_table
SET f_name = (
SELECT
REGEXP_SUBSTR(
( SELECT user_name FROM user_info
WHERE ROWID = R_ID ('user_info', p_table.rowid)
),
'[^ ]{1,15}', 1, 1
)
FROM DUAL
)
SQLFiddle example.
Does it do what you want without the subquery?
UPDATE p_table
SET f_name = (SELECT REGEXP_SUBSTR(user_name, '[^ ]{1,15}', 1, 1)
FROM user_info
WHERE ROWID = R_ID ('user_info')
);