I need to run a query on generated generated column names.
Here's the query:
select 'col_'||4 from MY_TABLE
Note:
"4" is a variable that is passed to this query from within the Java code
MY_TABLE is a table that contain columns with names (col_4, col_5, etc..)
Inside Oracle you need use dynamic SQL. (YourVariable value is 4 for your example)
EXECUTE IMMEDIATE ' select col_' || YourVariable || ' from MY_TABLE ';
From Java you can build any SQL and execute them
To run a dynamic SELECT statement, you have two choices:
For single row selects, you use EXECUTE IMMEDIATE ... INTO:
EXECUTE IMMEDIATE 'select col_' || l_num || ' from MY_TABLE WHERE id = 37' INTO l_result;
For selecting multiple rows, you can use a dynamic cursor:
DECLARE
TYPE MyCurType IS REF CURSOR;
my_cv MyCurType;
BEGIN
OPEN emp_cv FOR 'select col_' || l_num || ' from MY_TABLE';
...
END;
This code generates a SELECT that returns the tables with their column name:
SELECT
'SELECT ' ||(
SELECT
LISTAGG(
c.TABLE_NAME || '.' || c.COLUMN_NAME || ' AS "' || c.TABLE_NAME || '.' || c.COLUMN_NAME || '"',
', '
) WITHIN GROUP(
ORDER BY
c.TABLE_NAME
) "TABLE_NAMES"
FROM
USER_TAB_COLS c
WHERE
TABLE_NAME IN(
'PESSOA',
'PESSOA_FISICA',
'PESSOA_JURIDICA'
)
)|| 'FROM PERSON;'
FROM
DUAL;
Related
I am running a query on ALL_TAB_COLUMNS to select for column_names where it contains the name customer, then enter these tables and LISTAGG the values from these columns.
However, I get an exceptionally long error that I cannot understand:
PL/SQL: ORA-00942: table or view does not exist
ORA-06550: line 10, column 1:
PL/SQL: SQL Statement ignored
ORA-06550: line 15, column 22:
PLS-00364: loop index variable 'TB' use is invalid
ORA-06550: line 15, column 1:
PL/SQL: Statement ignored
06550. 00000 - "line %s, column %s:\n%s"
Here is what I have tried:
DECLARE
vcol VARCHAR2(128);
vtable VARCHAR(128);
BEGIN
FOR VAL IN (SELECT COLUMN_NAME, TABLE_NAME FROM ALL_TAB_COLUMNS WHERE COLUMN_NAME LIKE '%Customer%' AND DATA_TYPE in ( 'CHAR' , 'VARCHAR2' ))
LOOP
vcol := VAL.COLUMN_NAME;
vtable := VAL.TABLE_NAME;
FOR TB IN (
WITH A AS (
SELECT DISTINCT vcol FROM vtable
) SELECT LISTAGG(vcol, ',') as cols FROM A
)
LOOP
dbms_output.put_line(TB.cols);
END LOOP;
END LOOP;
END;
You can't refer to table and column names using run-time variables, unless you use dynamic SQL. You could construct each statement as a string, then open the cursor dynamically using that query string:
DECLARE
vstmt VARCHAR2(4000);
vresult VARCHAR2(4000);
vcursor SYS_REFCURSOR;
BEGIN
FOR VAL IN (SELECT COLUMN_NAME, TABLE_NAME FROM ALL_TAB_COLUMNS WHERE COLUMN_NAME LIKE '%Customer%')
LOOP
vstmt := 'WITH A AS (
SELECT DISTINCT "' || VAL.COLUMN_NAME || '" FROM "' || VAL.TABLE_NAME || '"
) SELECT LISTAGG("' || VAL.COLUMN_NAME || '", '','') FROM A';
OPEN vcursor FOR vstmt;
LOOP
FETCH vcursor INTO vresult;
EXIT WHEN vcursor%NOTFOUND;
dbms_output.put_line(vresult);
END LOOP;
END LOOP;
END;
/
Or as the lack of a WITHIN GROUP clause on your LISTAGG implies you're on 19c or later, you can simplify the dynamic statement to:
vstmt := 'SELECT LISTAGG(DISTINCT "' || VAL.COLUMN_NAME || '", '','') FROM "' || VAL.TABLE_NAME || '"';
You can also do the same thing without PL/SQL, using an XML trick do handle the dynamic statement:
select table_name, column_name,
xmlquery('/ROWSET/ROW/C/text()'
passing xmltype(dbms_xmlgen.getxml(
'select listagg(distinct "' || column_name || '", '','') as c '
|| 'from "' || table_name || '"'))
returning content) as value_list
from all_tab_columns
where column_name like '%Customer%';
Your filter where column_name like '%Customer%' implies you have quoted identifiers. If that's not the case then the column name will be in uppercase by default; but you could search for any case with where upper(column_name) like '%CUSTOMER%'.
And as you're looking up the tables and columns from all_tables, not user_tables, you should really be specifying the owner as well, whether you stick with PL/SQL or use the XML approach:
select owner, table_name, column_name,
xmlquery('/ROWSET/ROW/C/text()'
passing xmltype(dbms_xmlgen.getxml(
'select listagg(distinct "' || column_name || '", '','') as c '
|| 'from "' || owner || '"."' || table_name || '"'))
returning content) as value_list
from all_tab_columns
where upper(column_name) like '%CUSTOMER%';
fiddle including some dummy tables.
I would like to display results of dynamic sql based on antoher sql, but get error message. My code:
DECLARE
sql_qry VARCHAR2(1000) := NULL;
TYPE results IS
TABLE OF all_tab_columns%rowtype;
results_tbl results;
BEGIN
FOR i IN (
SELECT
*
FROM
all_tab_columns
WHERE
owner = 'OWNER_XYZ'
AND upper(column_name) LIKE '%COLUMN_XYZ%'
ORDER BY
table_name,
column_name
) LOOP
sql_qry := ' SELECT DISTINCT '
|| i.column_name
|| ' as column_name '
|| ' FROM '
|| i.owner
|| '.'
|| i.table_name
|| ' WHERE SUBSTR('
|| i.column_name
|| ',1,1) = ''Y''';
EXECUTE IMMEDIATE sql_qry BULK COLLECT
INTO results_tbl;
dbms_output.put_line(results_tbl);
END LOOP;
END;
I get the error message:
PLS-00306: wrong number or types of arguments in call to 'PUT_LINE'
In fact I need the results of all queries with an union between them like that
[1] [1]: https://i.stack.imgur.com/llxzr.png
Your dynamic query is selecting a single column, but you are bulk collecting into results_tbl, which is of type results, based on all_tab_columns%rowtype - which has lots of columns.
If you define your collection type as a single column of the data type you need, i.e. some length of string:
DECLARE
sql_qry VARCHAR2(1000) := NULL;
TYPE results IS
TABLE OF varchar2(4000);
results_tbl results;
...
You will then bulk collect a single column into that single-column collection. To display the results you need to loop over the collection:
FOR j IN 1..results_tbl.COUNT loop
dbms_output.put_line(results_tbl(j));
END LOOP;
so the whole block becomes:
DECLARE
sql_qry VARCHAR2(1000) := NULL;
TYPE results IS
TABLE OF varchar2(4000);
results_tbl results;
BEGIN
FOR i IN (
SELECT
*
FROM
all_tab_columns
WHERE
owner = 'OWNER_XYZ'
AND upper(column_name) LIKE '%COLUMN_XYZ%'
ORDER BY
table_name,
column_name
) LOOP
sql_qry := ' SELECT DISTINCT '
|| i.column_name
|| ' as column_name '
|| ' FROM '
|| i.owner
|| '.'
|| i.table_name
|| ' WHERE SUBSTR('
|| i.column_name
|| ',1,1) = ''Y''';
EXECUTE IMMEDIATE sql_qry BULK COLLECT
INTO results_tbl;
FOR j IN 1..results_tbl.COUNT loop
dbms_output.put_line(results_tbl(j));
END LOOP;
END LOOP;
END;
/
However, you can also do this without PL/SQL, using a variation on an XML trick. You can get the results of the dynamic query as an XML document using something like:
select dbms_xmlgen.getxmltype(
'select distinct "' || column_name || '" as value'
|| ' from "' || owner || '"."' || table_name || '"'
|| ' where substr("' || column_name || '", 1, 1) = ''Y'''
)
from all_tab_columns
where owner = 'OWNER_XYZ'
and upper(column_name) like '%COLUMN_XYZ%';
and then extract the value you want from that:
with cte (xml) as (
select dbms_xmlgen.getxmltype(
'select distinct "' || column_name || '" as value'
|| ' from "' || owner || '"."' || table_name || '"'
|| ' where substr("' || column_name || '", 1, 1) = ''Y'''
)
from all_tab_columns
where owner = 'OWNER_XYZ'
and upper(column_name) like '%COLUMN_XYZ%'
)
select x.value
from cte
cross apply xmltable(
'/ROWSET/ROW'
passing cte.xml
columns value varchar2(4000) path 'VALUE'
) x;
You can also easily include the table each value came from if you want that information (and the owner, and actual column name, etc.).
db<>fiddle showing both approaches.
I work wirh oracle Database. I have a plsql code where i run a query in a loop for multiple tables. so, table name is a variable in my code. I would like to have another variable (a single number) that I can call inside the loop and every time it counts the total rows of each table for me
declare
Cursor C_TABLE is
select trim(table_name) as table_name
from all_tables
where table_name in ('T1', 'T2', 'T3');
V_ROWNUM number;
begin
for m in C_TABLE
loop
for i in ( select column_name
from (
select c.column_name
from all_tab_columns c
where c.table_name = m.table_name
and c.owner = 'owner1'
)
)
loop
--I have this:
execute immediate ' insert into MY-table value (select ' || i.column_name || ' from ' || m.table_name || ')';
--I want this but it does not work of course:
V_ROWNUM := execute immediate 'select count(*) from ' || m.table_name;
execute immediate ' insert into MY-table value (select ' || i.column_name || ', ' || V_ROWNUM || ' from ' || m.table_name || ')';
end loop;
end loop;
end;
/
I count not use the "insert into" because I am not selecting from 1 table but the table I want to select from changes every round.
There are three things wrong with your dynamic SQL.
EXECUTE IMMEDIATE is not a function: the proper syntax is execute immediate '<<query>>' into <<variable>>.
An INSERT statement takes a VALUES clause or a SELECT but not both. SELECT would be very wrong in this case. Also note that it's VALUES not VALUE.
COLUMN_NAME is a string literal in the dynamic SQL so it needs to be in quotes. But because the SQL statement is itself a string, quotes in dynamic strings need to be escaped so it should be `'''||column_name||'''.
So the corrected version will look something like this
declare
Cursor C_TABLE is
select trim(table_name) as table_name
from all_tables
where table_name in ('T1', 'T2', 'T3');
V_ROWNUM number;
begin
for m in C_TABLE
loop
for i in ( select column_name
from (
select c.column_name
from all_tab_columns c
where c.table_name = m.table_name
and c.owner = 'owner1'
)
)
loop
execute immediate 'select count(*) from ' || m.table_name into V_ROWNUM;
execute immediate 'insert into MY_table values ( ''' || i.column_name || ''', ' || V_ROWNUM || ')';
end loop;
end loop;
end;
/
Dynamic SQL is hard because it turns compilation errors into runtime errors. It is good practice to write the statements first as static SQL. Once you have got the basic syntax right you can convert it into dynamic SQL.
you can't assign the result of execute immediate to a variable. it is not a function.
but you can do it by using the into_clause e.g.
execute immediate 'select count(*) from ' || m.table_name into V_ROWNUM ;
I'd like to find all column of a set of table with null values in them.
I can find the table and column names
SELECT TABLE_NAME, COLUMN_NAME
FROM user_tab_cols
where nullable='Y'
and table_name in ('myTalbe', 'myTable2');
And also check if the are nulls
select count(*) from myTable where myColumn is null;
but how can I put this toghether to have as result
table_name column_name
myTable myColumn
myTable myCol2
myTable2 col4
An approach could be with some dynamic SQL, but this would require some PL/SQL code; the following only uses SQL to get the result you need:
select *
from (
select table_name,
column_name,
to_number(extractvalue(xmltype(dbms_xmlgen.getxml('select count(*) c from '||table_name || ' where ' || column_name || ' is null')),'/ROWSET/ROW/C')) as rowcount
from user_tab_columns
where nullable='Y'
and table_name in ('myTalbe', 'myTable2')
)
where rowcount > 0
This could be an approach with dynamic SQL:
declare
type tableOfNumber is table of number;
type tableOfChar is table of varchar2(30);
--
vSQl varchar2(4000);
vListNumbers tableOfNumber;
vListTables tableOfChar;
vListColumns tableOfChar;
begin
select listagg( 'select ''' ||
table_name || ''' as table_name, ''' ||
column_name || ''' as column_name, count(*) as rowCount from ' ||
table_name ||
' where ' ||
column_name ||
' is null having count(*) > 0' ,
' UNION ALL '
) within group ( order by table_name, column_name)
into vSQL
from user_tab_columns
where nullable='Y'
and table_name in ('myTalbe', 'myTable2');
--
dbms_output.put_line(vSQL);
/* whatever you may want to do with the query */
/* for example, fetch into some variables and print the result */
execute immediate vSQL
bulk collect into vListTables, vListColumns, vListNumbers;
--
if vListTables.count() > 0 then
for i in vListTables.first .. vListTables.last loop
dbms_output.put_line('Table ' || vListTables(i) ||
', column ' || vListColumns(i) ||
', number of nulls: ' || vListNumbers(i)
);
end loop;
end if;
end;
Here's a routine I wrote a while back to do exactly that. It will output the required DDL to make those columns that are nullable (but do not contain any nulls) not nullable.
https://connormcdonald.wordpress.com/2016/03/11/tightening-up-your-data-model/
It can do the task for a schema or a single table.
I'm going mental over this. I'm fairly new to dynamic SQL, so I may just not be asking Google the right question, but here's what I'm trying to do... I have a query with dynamic SQL. When I run that query, it produces several rows. All of these rows (about 30) make up a single union query. I can copy all of those rows and paste into a new query and run - works fine, but what I need to do is run this all in a single query. I've looked up examples of using execute immediate and fetch, but I cannot seem to get them to actually spit out the data...they just end up saying something like "Executed Successfully", but doesn't actually produce any resulting rows. The resulting column name of the below SQL is "qry_txt" - instead of producing it at face value, I want to execute it as a query. Again, I may not be articulating this well, but I'm basically trying to turn 2 queries (with a manual copy/paste step involved) into a single query. Hope this makes sense...
Here's my SQL:
Select CASE when
lead(ROWNUM) over(order by ROWNUM) is null then
'SELECT '||''''||T.TABLE_NAME||''''||' as TABLE_NAME,'||''''||T.COLUMN_NAME||''''||' as COLUMN_NAME, cast('|| T.COLUMN_NAME ||' as
varchar2(100)) as SAMPLE_DATA ||
from rpt.'||T.TABLE_NAME ||' where '||T.COLUMN_NAME||' is not null and ROWNUM=1;'
else
'SELECT '||''''||T.TABLE_NAME||''''||' as TABLE_NAME,'||''''||T.COLUMN_NAME||''''||' as COLUMN_NAME, cast('|| T.COLUMN_NAME ||' as
varchar2(100)) as SAMPLE_DATA from rpt.'||T.TABLE_NAME ||' where '||T.COLUMN_NAME||' is not null and ROWNUM=1 union ' end as qry_txt
from all_tab_columns t where T.OWNER='rpt' and T.DATA_TYPE != 'BLOB' and T.DATA_TYPE != 'LONG' and T.TABLE_NAME = 'NME_DMN'
ORDER BY ROWNUM asc;
You cannot write a dynamic query in a SQL. You need to use PLSQL block to accomploish that. Please see how you can do it.
PS: Code is not tested.
declare
var1 <decalration same of column in select list> ;
var2 <decalration same of column in select list> ;
var3 <decalration same of column in select list> ;
....
varn ;
begin
for i in ( SELECT LEAD (ROWNUM) OVER (ORDER BY ROWNUM) COl1
FROM all_tab_columns t
WHERE T.OWNER = 'rpt'
AND T.DATA_TYPE != 'BLOB'
AND T.DATA_TYPE != 'LONG'
AND T.TABLE_NAME = 'NME_DMN'
ORDER BY ROWNUM ASC)
Loop
If i.col1 IS NULL Then
execute immediate 'SELECT '
|| ''''
|| T.TABLE_NAME
|| ''''
|| ' as TABLE_NAME,'
|| ''''
|| T.COLUMN_NAME
|| ''''
|| ' as COLUMN_NAME, cast('
|| T.COLUMN_NAME
|| ' as
varchar2(100)) as SAMPLE_DATA ||
from rpt.'
|| T.TABLE_NAME
|| ' where '
|| T.COLUMN_NAME
|| ' is not null and ROWNUM=1' into var1 , var2 ,var3 ....varn;
Else
execute immediate 'SELECT '
|| ''''
|| T.TABLE_NAME
|| ''''
|| ' as TABLE_NAME,'
|| ''''
|| T.COLUMN_NAME
|| ''''
|| ' as COLUMN_NAME, cast('
|| T.COLUMN_NAME
|| ' as
varchar2(100)) as SAMPLE_DATA from rpt.'
|| T.TABLE_NAME
|| ' where '
|| T.COLUMN_NAME
|| ' is not null and ROWNUM=1' into var1 , var2 ,var3 ....varn;
end if;
End Loop;
exception
when others then
dbms_output.put_lin(sqlcode ||'--'||sqlerrm);
End;