I'm building a query to be used in pagination, so my query looks like this:
open ref_cursor for
select * from TableA ta
join TableB tb on ta.id = tb.ta_id
where ta.conditionA = "searchParameter1"
where tb.conditionB = "searchParameter2"
order by ta.columnF
offset i_row_offset rows
fetch next i_row_fetch rows only
I would like to return this part as output parameter, before I offset/fetch the query results:
// I would like to get the row count of this part...
o_all_row_count := select count(*) from TableA ta
join TableB tb on ta.id = tb.ta_id
where ta.conditionA = "searchParameter1"
where tb.conditionB = "searchParameter2"
// And then slice if by offset/fetch only the rows that I want
select * from TableA ta
join TableB tb on ta.id = tb.ta_id
where ta.conditionA = "searchParameter1"
where tb.conditionB = "searchParameter2"
order by ta.columnF
offset i_row_offset rows
fetch next i_row_fetch rows only
I can definitely do this, but this looks like I'm gonna execute twice the same searching query. How do I do this better?
I don't think you can; in order to find out how many rows are there in a cursor, you have to fetch from it and yes - that's doing the same job twice.
You can get what you want, just not directly nor easily. What you need is to expand the cursor by a column. You then populate that column with the analytic version of count building a single partition:
select ...
, count(*) over() "rows in cursor"
from tablea a
join tableb b
on ( ... )
where ...;
This will in all likelihood also require you to actually specify your columns in the select (i.e. no select * ) and the subsequent fetch. See full example here.
Since I only use upper case to draw attention you can basically ignore everything except the upper case variables and the generated column in the open cursor select.
The question becomes: Is it worth the effort?
BTW your query
select * from TableA ta
join TableB tb on ta.id = tb.ta_id
where ta.conditionA = "searchParameter1"
where tb.conditionB = "searchParameter2"
is invalid. First off you can only have at most 1 WHERE clause per SELECT. Secondly, double quoting causes the value quoted to be interpreted as a variable name NOT a string constant. For value you need a single quote. The above should be:
select *
from TableA ta
join TableB tb on ta.id = tb.ta_id
where ta.conditionA = 'searchParameter1'
and tb.conditionB = 'searchParameter2'
...
I have this query.
SELECT re_current_benefits.prospect_nbr, qo_quote.quote_id, hra_ind, quote_type, effective_date, quote_expiration_ind, mhs_lob_code
FROM re_current_benefits
INNER JOIN qo_quote ON qo_quote.prospect_nbr = re_current_benefits.prospect_nbr
WHERE hra_ind = 'Y' AND quote_type = 'R' AND quote_expiration_ind IS NULL AND mhs_lob_code NOT IN 'DTL1' AND mhs_lob_code NOT IN 'DTL2'
And I need to pull the prospect_nbr from here, I also need to add a filter saying effective_date = renewal_date but if I do that by joining all 3 tables together I get 0 results which should not be the case.
SELECT prospect_nbr, rmr_run_status, renewal_date
FROM re_group
WHERE rmr_run_status = ANY ('S', 'W')
I have a query that doesn't work; can you help me with the transformation?
The original Informix query that I want to transform to Oracle.
SELECT DISTINCT table3.no_cev,
table1.literal,
table1.colid,
table2.repid,
table2.valor,
table2.indicador,
'',
'',
table2.origen,
table2.codi,
table2.no_cia,
table2.num_dcca,
table2.no_aprof,
table2.no_compta
FROM table1,
OUTER table2,
table3
WHERE ( table1.colid = table2.colid) and
( table1.grupid = table2.grupid) and
( table3.no_cev = table2.no_cev) and
( ( table1.grupid = 2) AND
( table2.cod_exp = 99609 ) AND
( table2.indicador = 'S' ) ) AND
( table3.num_dcca = 1);
( table3.codest = 76695);
My transformation of the query from Informix to Oracle — but it looks like it doesn't work:
SELECT DISTINCT table3.no_cev,
table1.literal,
table1.colid,
table2.repid,
table2.valor,
table2.indicador,
'',
'',
table2.origen,
table2.codi,
table2.no_cia,
table2.num_dcca,
table2.no_aprof,
table2.no_compta
FROM table1
LEFT OUTER JOIN (table2
RIGHT OUTER JOIN table3
ON table3.no_cev = table2.no_cev)
ON (( table1.colid = table2.colid)
AND ( table1.grupid = table2.grupid))
WHERE ( ( table1.grupid = '2' )
AND ( table2.cod_exp = '99609' )
AND ( table2.indicador = 'S' ) )
AND ( table3.num_dcca = '1')
AND ( table3.codest = '76695');
You have joined the table with ON clause at wrong place in the code.
Corrected your code now as following:
SELECT DISTINCT
TABLE3.NO_CEV,
TABLE1.LITERAL,
TABLE1.COLID,
TABLE2.REPID,
TABLE2.VALOR,
TABLE2.INDICADOR,
'',
'',
TABLE2.ORIGEN,
TABLE2.CODI,
TABLE2.NO_CIA,
TABLE2.NUM_DCCA,
TABLE2.NO_APROF,
TABLE2.NO_COMPTA
FROM
TABLE1
LEFT OUTER JOIN
-- ( -- removed this bracket
TABLE2 ON ( ( TABLE1.COLID = TABLE2.COLID )
AND ( TABLE1.GRUPID = TABLE2.GRUPID ) ) -- added this ON here
RIGHT OUTER JOIN TABLE3 ON TABLE3.NO_CEV = TABLE2.NO_CEV
-- ) -- removed this bracket
WHERE
TABLE1.GRUPID = '2'
AND TABLE2.COD_EXP = '99609'
AND TABLE2.INDICADOR = 'S'
AND TABLE3.NUM_DCCA = '1'
AND TABLE3.CODEST = '76695' ; -- no need of extra brackets
Cheers!!
It makes life unnecessarily difficult for people who would like to help you when you don't include a more or less minimal outline schema for the tables used in your query, and some sample data, and the expected results. Further, you seem to have converted numbers (integers) in the original Informix query into strings in the Oracle query. It is not clear why. Again, the schema would help explain what's going on.
As I noted in the comments, you should omit the two empty/null fields in the select-list; you could also drop a number of the columns from table2 — candidates for being dropped include all the columns not otherwise named in the query, such as repid, valor, origen, codi, no_cia, no_aprof, no_compta. Keep one or two of them; you don't really need more. However, I've preserved all the named columns in the sample data.
Schema and data
Here is some Informix SQL that appears to match the tables and columns in the query shown in the question. In case of doubt, the column was made into an INTEGER column. All the columns are qualified with NOT NULL.
DROP TABLE IF EXISTS table1;
DROP TABLE IF EXISTS table2;
DROP TABLE IF EXISTS table3;
CREATE TABLE table1
(
grupid INTEGER NOT NULL, -- 2
literal VARCHAR(32) NOT NULL,
colid INTEGER NOT NULL
);
CREATE TABLE table2
(
grupid INTEGER NOT NULL,
no_cev INTEGER NOT NULL,
colid INTEGER NOT NULL,
repid INTEGER NOT NULL,
valor INTEGER NOT NULL,
indicador CHAR(1) NOT NULL, -- 'S'
origen INTEGER NOT NULL,
codi INTEGER NOT NULL,
no_cia INTEGER NOT NULL,
num_dcca INTEGER NOT NULL,
no_aprof INTEGER NOT NULL,
no_compta INTEGER NOT NULL,
cod_exp INTEGER NOT NULL -- 99609
);
CREATE TABLE table3
(
no_cev INTEGER NOT NULL,
num_dcca INTEGER NOT NULL, -- 1
codest INTEGER NOT NULL -- 76695
);
LOAD FROM "table1.unl" INSERT INTO table1;
LOAD FROM "table2.unl" INSERT INTO table2;
LOAD FROM "table3.unl" INSERT INTO table3;
The annotations indicate the value specified in the query for that column; they helped guide the construction of the sample data.
Three sample data files in the Informix (pipe-separated values) UNLOAD format are:
table1.unl
2|Literal value 1|100
2|Literal value 2|123
2|Literal value 3|134
2|Literal value 4|145
table2.unl
2|2345|100|222|333|S|444|555|666|777|888|999|99609
2|2346|123|223|333|S|444|555|666|776|888|999|99609
2|2347|134|224|333|S|444|555|666|775|888|999|99609
2|2348|145|225|333|S|444|555|666|774|888|999|99609
1|2345|100|225|333|S|444|555|666|773|888|999|99609
2|2340|123|226|333|S|444|555|666|772|888|999|99609
3|2347|134|227|333|S|444|555|666|771|888|999|99609
2|2350|145|228|333|S|444|555|666|770|888|999|99609
table3.unl
2345|1|76695
2346|1|88776
2347|2|76695
2348|1|76695
Result of query using Informix-style OUTER join
Assuming that the stray early semicolon in the original query should be an AND (that matches what is written in the proposed Oracle query), removing the two empty string result columns, and removing the superfluous level of parentheses, then the original query looks like:
SELECT DISTINCT
table3.no_cev,
table1.literal,
table1.colid,
table2.repid,
table2.valor,
table2.indicador,
table2.origen,
table2.codi,
table2.no_cia,
table2.num_dcca,
table2.no_aprof,
table2.no_compta
FROM table1,
OUTER table2,
table3
WHERE (table1.colid = table2.colid) AND
(table1.grupid = table2.grupid) AND
(table3.no_cev = table2.no_cev) AND
(table1.grupid = 2) AND
(table2.cod_exp = 99609) AND
(table2.indicador = 'S') AND
(table3.num_dcca = 1) AND
(table3.codest = 76695);
On the sample data shown, using Informix 12.10.FC6 running on a MacBook Pro with macOS 10.14.6 Mojave (not that the o/s is likely to be a factor in the results), this produces:
2345|Literal value 1|100|222|333|S|444|555|666|777|888|999
2345|Literal value 2|123|||||||||
2345|Literal value 3|134|||||||||
2345|Literal value 4|145|||||||||
2348|Literal value 1|100|||||||||
2348|Literal value 2|123|||||||||
2348|Literal value 3|134|||||||||
2348|Literal value 4|145|225|333|S|444|555|666|774|888|999
Why, you ask? Good question! The Informix old-style OUTER join is a complex critter, and doesn't necessarily have a simple translation to modern standard SQL (and hence to Oracle, etc). You can find some description of the way it works at Complex Outer Joins.
There are two groups of tables — table1 and table3 are the dominant tables, and table2 is the only OUTER table here. This means that Informix processes table1 and table3 using inner join, and then outer joins the result with table2. Since there is no direct join between table1 and table3, the result is a cartesian product of the two tables — each of the 4 rows in table1 is joined with each of the 4 rows in table3, yielding 16 rows. However, the filter conditions eliminate the rows from table3 where no_cev is 2346 and 2347. All the remaining 8 rows will be preserved, regardless of the results of the outer join operation. Now the rows are outer joined with table2. The rows with (no_cev, colid) of (2345, 100) and (2348, 145) have matching rows in table3 where the data satisfies the conditions in the WHERE clause. The other rows don't have such matching rows so the columns from table2 for those rows are 'all NULL'. As I said, it is weird — contorted. And explaining is hard work!
A first approximation using standard SQL
This query is a moderate approximation to a direct translation of the Informix query:
SELECT DISTINCT
t3.no_cev,
t1.literal,
t1.colid,
t2.repid,
t2.valor,
t2.indicador,
t2.origen,
t2.codi,
t2.no_cia,
t2.num_dcca,
t2.no_aprof,
t2.no_compta
FROM table1 AS t1
INNER JOIN table3 AS t3 ON 1 = 1
LEFT JOIN table2 AS t2 ON t3.no_cev = t2.no_cev
AND t1.colid = t2.colid
AND t1.grupid = t2.grupid
WHERE t1.grupid = 2
AND t2.cod_exp = 99609
AND t2.indicador = 'S'
AND t3.num_dcca = 1
AND t3.codest = 76695;
The output is:
2345|Literal value 1|100|222|333|S|444|555|666|777|888|999
2348|Literal value 4|145|225|333|S|444|555|666|774|888|999
This is missing the rows with 'null values'.
Achieving the same result using standard INNER and OUTER joins
We can collect those rows by looking for rows where one of the columns in table2 is null (because they're either all null or none null — because the columns are qualified NOT NULL):
SELECT DISTINCT
t3.no_cev,
t1.literal,
t1.colid,
t2.repid,
t2.valor,
t2.indicador,
t2.origen,
t2.codi,
t2.no_cia,
t2.num_dcca,
t2.no_aprof,
t2.no_compta
FROM table1 AS t1
INNER JOIN table3 AS t3 ON 1 = 1
LEFT JOIN table2 AS t2 ON t3.no_cev = t2.no_cev
AND t1.colid = t2.colid
AND t1.grupid = t2.grupid
WHERE t1.grupid = 2
AND ((t2.cod_exp = 99609 AND t2.indicador = 'S') OR t2.cod_exp IS NULL)
AND t3.num_dcca = 1
AND t3.codest = 76695;
This yields the output:
2345|Literal value 1|100|222|333|S|444|555|666|777|888|999
2345|Literal value 2|123|||||||||
2345|Literal value 3|134|||||||||
2345|Literal value 4|145|||||||||
2348|Literal value 1|100|||||||||
2348|Literal value 2|123|||||||||
2348|Literal value 3|134|||||||||
2348|Literal value 4|145|225|333|S|444|555|666|774|888|999
This is the same as the original old-style Informix OUTER join query.
Tejash's proposed solution
The SQL in Tejash's answer (revision 1) yields, on the same data:
2345|Literal value 1|100|222|333|S|\ |\ |444|555|666|777|888|999
2348|Literal value 4|145|225|333|S|\ |\ |444|555|666|774|888|999
The backslash-space values correspond to the empty strings — it's Informix's slightly peculiar way of encoding a zero-length non-null string. It's an area where Oracle may well behave slightly differently, but it is tangential to the problem with the query.
Clearly, this is not the same result as the Informix query. It's probably more reasonable; it works out of the box (I simply did copy'n'paste, quoted numbers and all, and it worked with no editing needed).
I don't know about Informix OUTER syntax, so my answer may be wrong. The WHERE clause, however, lacking any relation between table1 and table3 suggests that this is just a cross join of table1 and table3 and then an outer join of table2.
One way to write this:
select t3.no_cev, t1.literal, t1.colid, t2.*
from table1 t1
cross join table3 t3
left join table2 t2 on t2.colid = t1.colid
and t2.grupid = t1.grupid
and t2.no_cev = t3.no_cev
and t2.cod_exp = 2
and t2.indicador = 'S'
where t1.grupid = 2
and t3.num_dcca = 1
and t3.codest = 76695;
Another is:
with t1 as (select * from table1 where grupid = 2)
, t2 as (select * from table1 where grupid = 2 and cod_exp = 2 and indicador = 'S')
, t3 as (select * from table3 where num_dcca = 1 and codest = 76695)
select t3.no_cev, t1.literal, t1.colid, t2.*
from t1
cross join t3
left join t2 on t2.colid = t1.colid and t2.no_cev = t3.no_cev;
Above queries are standard SQL and supported by Oracle as of version 9i I think.
I am new to Oracle. I am trying to update the values of a table with the values from a SELECT DISTINCT statement using the MERGE INTO method. I want to update the values for a table based on what is in the USING table conditionally.
A quick diagram of what I am essentially going for is
MERGE
INTO update_table ut
USING
(SELECT DISTINCT
t1.column_1
,t2.column_2
FROM table_1 t1
INNER JOIN table_2 t2
ON t1.foreign_key = t2.primary_key) st
ON (ut.pk = st.column_1)
WHEN MATCH UPATE
SET(ut.update_column = st.column_2
WHERE st.column_1 = 1
AND st.column_2 = 1
,ut.update_column = st.column_2
WHERE st.column_1 = 2
AND st.column_2 = 2);
However, when I do so I get the INVALID COLUMN SPECIFICATION error on the line where I use SET. How can I work around this to successfully update the table, preferably in ANSI standard?
You can include the conditions that you have added in where clause in the selected column list in using clause itself. Like This. (Not tested. Your conditions in where clause were not appropriate)
MERGE
INTO update_table ut
USING (SELECT DISTINCT
t1.column_1 ,
CASE
WHEN t1.column_1 = 1
AND t2.column_2 = 1
THEN t2.column_1
WHEN t1.column_1 = 2
AND t2.column_2 = 2
THEN t2.column_2
END column_2
FROM
table_1 t1
INNER JOIN table_2 t2 ON t1.foreign_key = t2.primary_key
) st
ON (ut.pk = st.column_1)
WHEN MATCHED THEN
UPDATE SET ut.update_column = st.column_2 ;
I am attempting to figure out if a column in Oracle is populated from a sequence. My impression of how Oracle handles sequencing is that the sequence and column are separate entities and one needs to either manually insert the next sequence value like:
insert into tbl1 values(someseq.nextval, 'test')
or put it into a table trigger. Meaning that it is non-trivial to tell if a column is populated from a sequence. Is that correct? Any ideas about how I might go about figuring out if a column is populated from a sequence?
You are correct; the sequence is separate from the table, and a single sequence can be used to populate any table, and the values in a column in some table may mostly come from a sequence (or set of sequences), except for the values manually generated.
In other words, there is no mandatory connection between a column and a sequence - and therefore no way to discover such a relationship from the schema.
Ultimately, the analysis will be of the source code of all applications that insert or update data in the table. Nothing else is guaranteed. You can reduce the scope of the search if there is a stored procedure that is the only way to make modifications to the table, or if there is a trigger that sets the value, or other such things. But the general solution is the 'non-solution' of 'analyze the source'.
If the sequence is used in a trigger, it is possible to find which tables it populates:
SQL> select t.table_name, d.referenced_name as sequence_name
2 from user_triggers t
3 join user_dependencies d
4 on d.name = t.trigger_name
5 where d.referenced_type = 'SEQUENCE'
6 and d.type = 'TRIGGER'
7 /
TABLE_NAME SEQUENCE_NAME
------------------------------ ------------------------------
EMP EMPNO_SEQ
SQL>
You can vary this query to find stored procedures, etc that make use of the sequence.
There are no direct metadata links between Oracle sequences and any use in the database. You could make an intelligent guess if a column's values are related to a sequence by querying the USER_SEQUENCES metadata and comparing the LAST_NUMBER column to the data for the column.
select t.table_name,
d.referenced_name as sequence_name,
d.REFERENCED_OWNER as "OWNER",
c.COLUMN_NAME
from user_trigger_cols t, user_dependencies d, user_tab_cols c
where d.name = t.trigger_name
and t.TABLE_NAME = c.TABLE_NAME
and t.COLUMN_NAME = c.COLUMN_NAME
and d.referenced_type = 'SEQUENCE'
and d.type = 'TRIGGER'
As Jonathan pointed out: there is no direct way to relate both objects. However, if you "keep a standard" for primary keys and sequences/triggers you could find out by finding the primary key and then associate the constraint to the table sequence.
I was in need of something similar since we are building a multi-db product and I tried to replicate some classes with properties found in a DataTable object from .Net which has AutoIncrement, IncrementSeed and IncrementStep which can only be found in the sequences.
So, as I said, if you, for your tables, use a PK and always have a sequence associated with a trigger for inserts on a table then this may come handy:
select tc.table_name,
case tc.nullable
when 'Y' then 1
else 0
end as is_nullable,
case ac.constraint_type
when 'P' then 1
else 0
end as is_identity,
ac.constraint_type,
seq.increment_by as auto_increment_seed,
seq.min_value as auto_increment_step,
com.comments as caption,
tc.column_name,
tc.data_type,
tc.data_default as default_value,
tc.data_length as max_length,
tc.column_id,
tc.data_precision as precision,
tc.data_scale as scale
from SYS.all_tab_columns tc
left outer join SYS.all_col_comments com
on (tc.column_name = com.column_name and tc.table_name = com.table_name)
LEFT OUTER JOIN SYS.ALL_CONS_COLUMNS CC
on (tc.table_name = cc.table_name and tc.column_name = cc.column_name and tc.owner = cc.owner)
LEFT OUTER JOIN SYS.ALL_CONSTRAINTS AC
ON (ac.constraint_name = cc.constraint_name and ac.owner = cc.owner)
LEFT outer join user_triggers trg
on (ac.table_name = trg.table_name and ac.owner = trg.table_owner)
LEFT outer join user_dependencies dep
on (trg.trigger_name = dep.name and dep.referenced_type='SEQUENCE' and dep.type='TRIGGER')
LEFT outer join user_sequences seq
on (seq.sequence_name = dep.referenced_name)
where tc.table_name = 'TABLE_NAME'
and tc.owner = 'SCHEMA_NAME'
AND AC.CONSTRAINT_TYPE = 'P'
union all
select tc.table_name,
case tc.nullable
when 'Y' then 1
else 0
end as is_nullable,
case ac.constraint_type
when 'P' then 1
else 0
end as is_identity,
ac.constraint_type,
seq.increment_by as auto_increment_seed,
seq.min_value as auto_increment_step,
com.comments as caption,
tc.column_name,
tc.data_type,
tc.data_default as default_value,
tc.data_length as max_length,
tc.column_id,
tc.data_precision as precision,
tc.data_scale as scale
from SYS.all_tab_columns tc
left outer join SYS.all_col_comments com
on (tc.column_name = com.column_name and tc.table_name = com.table_name)
LEFT OUTER JOIN SYS.ALL_CONS_COLUMNS CC
on (tc.table_name = cc.table_name and tc.column_name = cc.column_name and tc.owner = cc.owner)
LEFT OUTER JOIN SYS.ALL_CONSTRAINTS AC
ON (ac.constraint_name = cc.constraint_name and ac.owner = cc.owner)
LEFT outer join user_triggers trg
on (ac.table_name = trg.table_name and ac.owner = trg.table_owner)
LEFT outer join user_dependencies dep
on (trg.trigger_name = dep.name and dep.referenced_type='SEQUENCE' and dep.type='TRIGGER')
LEFT outer join user_sequences seq
on (seq.sequence_name = dep.referenced_name)
where tc.table_name = 'TABLE_NAME'
and tc.owner = 'SCHEMA_NAME'
AND AC.CONSTRAINT_TYPE is null;
That would give you the list of columns for a schema/table with:
Table name
If column is nullable
Constraint type (only for PK's)
Increment seed (from the sequence)
Increment step (from the sequence)
Column comments
Column name, of course :)
Data type
Default value, if any
Length of column
Index (column id)
Precision (for numbers)
Scale (for numbers)
I'm pretty sure that code can be optimized but it works for me, I use it to "load metadata" for tables and then represent that metadata as entities on my frontend.
Note that I'm filtering only primary keys and not retrieving compound key constraints since I don't care about those. If you do you'll have to modify the code to do so and make sure that you filter duplicates since you could get one column twice (one for the PK constraint, another for the compound key).