I'm using sqlfluff to lint my postges code. I'm down to a single linting error, in my test code, that I dont know how to fix by adjusting my sql nor how to configure it.
The rules im breaking is L025.
The issue is that sqlfluff thinks, i'm not using the alias i because I dont write womething like i.value.
With the following code:
insert into private.account (
account_first_name,
account_last_name,
account_display_name,
account_email,
account_password
)
select
'Random' as account_first_name,
'User' as account_last_name,
concat('Random User ', i) as account_display_name,
concat('random', i, '#email.com') as account_email,
gen_random_hash() as account_password
from generate_series(1, 200) as i;
and the coresponding error:
== [test\generate_accounts.sql] FAIL
L: 38 | P: 33 | L025 | Alias 'i' is never used in SELECT statement.
All Finished!
I do agree with the linter here. i is a table alias and shouldn't be used as a column reference. It's cleaner to use
from generate_series(1, 200) as g(i)
or whatever naming you prefer.
Then reference the value as g.i
Related
Consider the following xml document that is stored in a PostgreSQL field:
<E_sProcedure xmlns="http://www.minushabens.com/2008/FMSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" modelCodeScheme="Emo_ex" modelCodeSchemeVersion="01" modelCodeValue="EMO_E_PROCEDURA" modelCodeMeaning="Section" sectionID="11">
<tCatSnVsn_Pmax modelCodeScheme="Emodinamica_referto" modelCodeSchemeVersion="01" modelCodeValue="tCat4" modelCodeMeaning="My text"><![CDATA[1]]></tCatSnVsn_Pmax>
</E_sProcedure>
If I run the following query I get the correct result for Line 1, while Line 2 returns nothing:
SELECT
--Line 1
TRIM(BOTH FROM array_to_string((xpath('//child::*[#modelCodeValue="tCat4"]/text()', t.xml_element)),'')) as tCatSnVsn_Pmax_MEANING
--Line2
,TRIM(BOTH FROM array_to_string((xpath('/tCatSnVsn_Pmax/text()', t.xml_element)),'')) as tCatSnVsn_Pmax
FROM (
SELECT unnest(xpath('//x:E_sProcedure', s.XMLDATA::xml, ARRAY[ARRAY['x', 'http://www.minushabens.com/2008/FMSchema']])) AS xml_element
FROM sr_data as s)t;
What's wrong in the xpath of Line 2?
Your second xpath() doesn't return anything because of two problems. First: you need to use //tCatSnVsn_Pmax as the xml_element still starts with <E_sProcedure>. The path /tCatSnVsn_Pmax tries to select a top-level element with that name.
But even then, the second one won't return anything because of the namespace. You need to pass the same namespace definition to the xpath(), so you need something like this:
SELECT (xpath('/x:tCatSnVsn_Pmax/text()', t.xml_element, ARRAY[ARRAY['x', 'http://www.minushabens.com/2008/FMSchema']]))[1] as tCatSnVsn_Pmax
FROM (
SELECT unnest(xpath('//x:E_sProcedure', s.XMLDATA::xml, ARRAY[ARRAY['x', 'http://www.minushabens.com/2008/FMSchema']])) AS xml_element
FROM sr_data as s
)t;
With modern Postgres versions (>= 10) I prefer using xmltable() for anything nontrivial. It makes passing namespaces easier and accessing multiple attributes or elements.
SELECT xt.*
FROM sr_data
cross join
xmltable(xmlnamespaces ('http://www.minushabens.com/2008/FMSchema' as x),
'/x:E_sProcedure'
passing (xmldata::xml)
columns
sectionid text path '#sectionID',
pmax text path 'x:tCatSnVsn_Pmax',
model_code_value text path 'x:tCatSnVsn_Pmax/#modelCodeValue') as xt
For your sample XML, the above returns:
sectionid | pmax | model_code_value
----------+------+-----------------
11 | 1 | tCat4
I am trying to add a declared variable to replace a hardcoded list of values in a "where in" clause.
Researching how Hana handles array variables it seems like I can do this by declaring an array and then either using a select directly on it or by unnesting it first into a table but I keep getting errors I can't resolve.
When I try it this way:
DO
BEGIN
DECLARE CODES_ARRAY NVARCHAR(100) ARRAY = ARRAY('01','02','03','04');
SELECT T0."ItemCode"
FROM OITM T0
INNER JOIN OITW T1 ON T0."ItemCode" = T1."ItemCode"
WHERE "WhsCode" IN (SELECT "code" FROM :CODES_ARRAY); -- line 9 where error occurs
END;
I get this error message sql syntax error: incorrect syntax near ")": line 9 col 54 (at pos 239)
I can't figure out what the syntax error resolution is.
So then I tried inserting a declared table variable like this:
DO
BEGIN
DECLARE CODES_ARRAY NVARCHAR(100) ARRAY = ARRAY('01','02','03','04');
DECLARE CODES_TABLE TABLE = UNNEST(:CODES_ARRAY) AS ("code"); -- line 5 where error occurs
SELECT T0."ItemCode"
FROM OITM T0
INNER JOIN OITW T1 ON T0."ItemCode" = T1."ItemCode"
WHERE "WhsCode" IN (SELECT "code" FROM CODES_TABLE); -- I know : is missing here but when adding, the same error from previous block shows up
END;
and I get this error message: identifier must be declared: 1: line 5 col 38 (at pos 123)
As far as I can tell the array variable is declared as it should be so I don't know how to resolve the error.
I've read the SAP Hana SQL Reference documentation (for array/table variables, unnest function, etc.) over and over and it seems like I've got everything setup correctly but can't figure out these errors. I would like to be able to use both of these approaches at different times if possible (the "array variable to table variable" and the "array variable only" approaches)
I don't know exactly what is going on here, but one thing I notice that the two different error messages referenced in my post (see difference from errors in the first two code blocks) is that each error is occurring either immediately before the use of the variable with the : (in the case of the UNNEST) or immediately following the variable with the : (in the case of using in the SELECT * FROM in the query).
Because of that, I wondered if the issue is "upstream" at the Hana ADO.NET application query preparation and execution call level, but I ran a test and when I double checked the query string just before it is executed, it appears unchanged and the variables with : still look as they should, so at least as far as just before execution through Hana ADO.NET HanaCommand it looks correct - but once executing the query using HanaDataReader or HanaDataAdapter it returns the error messages referred to above. It may be a red herring to chase the problem from the Hana ADO.NET level but don't know what else to do.
Update
To further troubleshoot, I tried executing this code block below using hdbsql.exe -n XXX.XXX.XXX.XXX:30015 -u XXX -p XXX -m -I "c:\temp\test.sql" -c "#" and it works! So, the errors I see only show up when executing the same query through the Hana ADO.NET interface.
DO
BEGIN
DECLARE CODES_ARRAY NVARCHAR(10) ARRAY = ARRAY('01','02','03','04');
DECLARE CODES_TABLE TABLE ("code" NVARCHAR(10)) = UNNEST(:CODES_ARRAY) AS ("code");
SELECT T0."ItemCode"
FROM OITM T0
INNER JOIN OITW T1 ON T0."ItemCode" = T1."ItemCode"
WHERE "WhsCode" IN (SELECT "code" FROM :CODES_TABLE); -- line 10 where error occurs when using Hana ADO.NET
END;
#
The above fails when through Hana ADO.NET with the error message: sql syntax error: incorrect syntax near ")": line 10 col 54 (at pos 325) but works when executed through hdbsql.
Update
The C# code that executes the query is fairly straight forward, but for completeness of troubleshooting effort I am including the interesting parts of our HanaHelper class. This code works successfully to execute 100s of queries a day without errors or problems. This is the first time where a variable of any type has been attempted to be declared or used in a query through this code and when the errors started showing up. As far as I can tell, the issue is tied to the use of the : when using the variable in the query.
public class HanaHelper
{
public HanaConnection objConn = null;
public HanaHelper(string ConnectionString)
{
try
{
objConn = new HanaConnection(ConnectionString);
}
catch (Exception e)
{
Console.WriteLine(#"Exception thrown by HanaConnection: {0}\n{1}", e.Message, e.InnerException);
}
}
public DataSet GetData(string strSQL)
{
using (HanaCommand objCmd = new HanaCommand(strSQL, objConn))
{
using (HanaDataAdapter objDA = new HanaDataAdapter(objCmd))
{
DataSet objDS = new DataSet();
try
{
objDA.Fill(objDS);
}
catch (Exception)
{
throw;
}
finally
{
// do something interesting regardless of success or failure
}
objConn.Close();
return objDS;
}
}
}
}
Any clue here why the same query works through hdbsql but fails when executing through Hana ADO.NET?
Update
I figured out how to use HanaSQLTrace in the C# code so that I can inspect the prepared query text and viola, the source of error messages becomes apparent, all occurrences of ":VARNAME" are replaced with "? " (a ? replaces the : and a space for each character in the variable name). I suppose it is trying to pre-substitute occurrences of : with a ? as if there were parameters to be substituted.
How can this behavior be disabled, or worked with, or worked around so that I can use variables in a query in Hana ADO.NET effectively?
Updated based on the OP feedback.
To refer to a variable (in order to access its value(s)) in SQLScript it's
necessary to put a colon : in front of the variable name.
The main issue, however, turns out to be the declaration of the CODES_TABLE table variable.
With HANA 2 SPS 4 the error message is
`SAP DBTech JDBC: [264]: invalid datatype: unknown type SYSTEM.TABLE: line 5 col 23`
This points to the declaration of the TABLE typed variable CODES_TABLE which lacks the definition of what columns should be in the table.
Adding this fixes the issue.
With these changes, your code should work:
DO
BEGIN
DECLARE CODES_ARRAY NVARCHAR(100) ARRAY = ARRAY('01','02','03','04');
DECLARE CODES_TABLE TABLE ("code" NVARCHAR(100)) = UNNEST(:CODES_ARRAY) AS ("code");
-- ^^^^^^^^^^^^^^^^^^^^^^
-- |
---------------------------------------+
SELECT
T0."ItemCode"
FROM
OITM T0
INNER JOIN OITW T1
ON T0."ItemCode" = T1."ItemCode"
WHERE
"WhsCode" IN (SELECT "code" FROM :CODES_TABLE);
-- ^
-- |
---------------------------------------+
END;
An alternative option to declare and assign the table variable is to not use the DECLARE command.
DO
BEGIN
DECLARE CODES_ARRAY NVARCHAR(100) ARRAY = ARRAY('01','02','03','04');
CODES_TABLE = UNNEST(:CODES_ARRAY) AS ("code");
SELECT
T0."ItemCode"
FROM
OITM T0
INNER JOIN OITW T1
ON T0."ItemCode" = T1."ItemCode"
WHERE
"WhsCode" IN (SELECT "code" FROM :CODES_TABLE);
END;
The ||-operator and the concat(...)-function in PostgreSQL behave differently.
select 'ABC'||NULL||'def';
-- Result: NULL
select concat('ABC', NULL, 'def');
-- Result: 'ABCdef'
concat(...) ignores NULL values, but a NULL whithin a || expression makes the whole result become NULL.
In JOOQ, the DSL.concat() in the PostgreSQL dialect renders expressions using the ||-operator:
Java: dsl.select(
DSL.concat(
DSL.inline("ABC"),
DSL.inline(null, SQLDataType.VARCHAR),
DSL.inline("def"))
).execute();
SQL: select ('ABC' || null || 'def')
Result: NULL
I am looking for (elegant?) ways to invoke the concat(...)-function instead of the ||-operator via JOOQ in PostgreSQL:
Java: dsl.select(???).execute();
SQL: select concat('ABC', null, 'def')
Result: 'ABCdef'
I found two ways to achieve the posed objective.
Approach #1:
dsl.select(
field(
"concat({0})",
SQLDataType.VARCHAR,
list(
inline("ABC"),
inline(null, SQLDataType.VARCHAR),
inline("def")
)
)
).execute();
This has to the intended behavior, but necessitates the in my eyes ugly "concat({0})". A more elegant approach from my point of view is:
Approach #2:
dsl.select(
function(
"concat",
SQLDataType.VARCHAR,
inline("ABC"),
inline(null, SQLDataType.VARCHAR),
inline("def")
)
).execute();
This solution does not involve inline SQL with placeholders as approach #1. Why JOOQ generates || instead of concat(...) in the first place is still to be expounded, though.
I have a SQL query which takes user inputs hence security flaw is present.
The existing query is:
SELECT BUS_NM, STR_ADDR_1, CITY_NM, STATE_CD, POSTAL_CD, COUNTRY_CD,
BUS_PHONE_NB,PEG_ACCOUNT_ID, GDN_ALERT_ID, GBIN, GDN_MON_REF_NB,
ALERT_DT, ALERT_TYPE, ALERT_DESC,ALERT_PRIORITY
FROM ( SELECT A.BUS_NM, AE.STR_ADDR_1, A.CITY_NM, A.STATE_CD, A.POSTAL_CD,
CC.COUNTRY_CD, A.BUS_PHONE_NB, A.PEG_ACCOUNT_ID, 'I' ||
LPAD(INTL_ALERT_DTL_ID, 9,'0') GDN_ALERT_ID,
LPAD(IA.GBIN, 9,'0') GBIN, IA.GDN_MON_REF_NB,
DATE(IAD.ALERT_TS) ALERT_DT,
XMLCAST(XMLQUERY('$A/alertTypeConfig/biqCode/text()' passing
IAC.INTL_ALERT_TYPE_CONFIG as "A") AS CHAR(4)) ALERT_TYPE,
, ROW_NUMBER() OVER () AS "RN"
FROM ACCOUNT A, Other tables
WHERE IA.GDN_MON_REF_NB = '100'
AND A.PEG_ACCOUNT_ID = IAAR.PEG_ACCOUNT_ID
AND CC.COUNTRY_CD = A.COUNTRY_ISO3_CD
ORDER BY IA.INTL_ALERT_ID ASC )
WHERE ALERT_TYPE IN (" +TriggerType+ ");
I changed it to accept TriggerType from setString like:
SELECT BUS_NM, STR_ADDR_1, CITY_NM, STATE_CD, POSTAL_CD, COUNTRY_CD,
BUS_PHONE_NB,PEG_ACCOUNT_ID, GDN_ALERT_ID, GBIN, GDN_MON_REF_NB,
ALERT_DT, ALERT_TYPE, ALERT_DESC,ALERT_PRIORITY
FROM ( SELECT A.BUS_NM, AE.STR_ADDR_1, A.CITY_NM, A.STATE_CD, A.POSTAL_CD,
CC.COUNTRY_CD, A.BUS_PHONE_NB, A.PEG_ACCOUNT_ID,
'I' || LPAD(INTL_ALERT_DTL_ID, 9,'0') GDN_ALERT_ID,
LPAD(IA.GBIN, 9,'0') GBIN, IA.GDN_MON_REF_NB,
DATE(IAD.ALERT_TS) ALERT_DT,
XMLCAST(XMLQUERY('$A/alertTypeConfig/biqCode/text()' passing
IAC.INTL_ALERT_TYPE_CONFIG as "A") AS CHAR(4)) ALERT_TYPE,
ROW_NUMBER() OVER () AS "RN"
FROM ACCOUNT A, other tables
WHERE IA.GDN_MON_REF_NB = '100'
AND A.PEG_ACCOUNT_ID = IAAR.PEG_ACCOUNT_ID
AND CC.COUNTRY_CD = A.COUNTRY_ISO3_CD
ORDER BY IA.INTL_ALERT_ID ASC )
WHERE ALERT_TYPE IN (?);
Setting trigger type as below:
if (StringUtils.isNotBlank(request.getTriggerType())) {
preparedStatement.setString(1, triggerType != null ? triggerType.toString() : "");
}
Getting error as
Caused by: com.ibm.db2.jcc.am.SqlDataException: DB2 SQL Error: SQLCODE=-302, SQLSTATE=22001, SQLERRMC=null, DRIVER=4.19.26
The -302 SQLCODE indicates a conversion error of some sort.
SQLSTATE 22001 narrows that down a bit by telling us that you are trying to force a big string into a small variable. Given the limited information in your question, I am guessing it is the XMLCAST that is the culprit.
DB2 won't jam 30 pounds of crap into a 4 pound bag so to speak, it gives you an error. Maybe giving XML some extra room in the cast might be a help. If you need to make sure it ends up being only 4 characters long, you could explicitly do a LEFT(XMLCAST( ... AS VARCHAR(64)), 4). That way the XMLCAST has the space it needs, but you cut it back to fit your variable on the fetch.
The other thing could be that the variable being passed to the parameter marker is too long. DB2 will guess the type and length based on the length of ALERT_TYPE. Note that you can only pass a single value through a parameter marker. If you pass a comma separated list, it will not behave as expected (unless you expect ALERT_TYPE to also contain a comma separated list). If you are getting the comma separated list from a table, you can use a sub-select instead.
Wrong IN predicate use with a parameter.
Do not expect that IN ('AAAA, M250, ABCD') (as you try to do passing a comma-separated string as a single parameter) works as IN ('AAAA', 'M250', 'ABCD') (as you need). These predicates are not equivalent.
You need some "string tokenizer", if you want to pass such a comma-separated string like below.
select t.*
from
(
select XMLCAST(XMLQUERY('$A/alertTypeConfig/biqCode/text()' passing IAC.INTL_ALERT_TYPE_CONFIG as "A") AS CHAR(4)) ALERT_TYPE
from table(values xmlparse(document '<alertTypeConfig><biqCode>M250, really big code</biqCode></alertTypeConfig>')) IAC(INTL_ALERT_TYPE_CONFIG)
) t
--WHERE ALERT_TYPE IN ('AAAA, M250, ABCD')
join xmltable('for $id in tokenize($s, ",\s?") return <i>{string($id)}</i>'
passing cast('AAA, M250 , ABCD' as varchar(200)) as "s"
columns token varchar(200) path '.') x on x.token=t.ALERT_TYPE
;
Run the statement as is. Then you may uncomment the string with WHERE clause and comment out the rest to see what you try to do.
P.S.:
The error you get is probably because you don't specify the data type of the parameter (you don't use something like IN (cast(? as varchar(xxx))), and db2 compiler assumes that its length is equal to the length of the ALERT_TYPE expression (4 bytes).
I am using PostgreSQL 9.1.4 with hstore and the PostgreSQL JDBC driver (9.1-901.jdbc4).
I am trying to use the contains operators (?, ?&, ?|) in a PreparedStatement, however the ? character is parsed as a variable placeholder. Can this character be escaped to send the correct operator in the query?
An example:
PreparedStatement stmt = conn.prepareStatement("SELECT a, b FROM table1 WHERE c ? 'foo' AND d = ?");
stmt.setInt(1, dValue);
stmt.executeQuery();
In this form the following example would raise an exception:
org.postgresql.util.PSQLException: No value specified for parameter 2.
Update:
After investigating the query parser in the pgjdbc driver this snippet seems to indicate that it is not possible to escape the ? character. The questions that remain are:
Is there anything in the JDBC spec which allows a ? to be escaped and be anything other than a parameter placeholder?
Is there any better work around for this issue than just using plain Statements with variables manually inserted into the query string?
Effectively, it looks like the java SQL parser is not hstore compliant.
But since the syntax c ? 'foo' is equivalent to exist(c, 'foo'), you can easily workaround this problem. Have a look at the following page to see what the verbose operators for hstore are.
Postgres hstore documentation
There is a discussion about this issue on pgsql-hackers mailing list: http://grokbase.com/t/postgresql/pgsql-hackers/1325c6ys9n/alias-hstores-to-so-that-it-works-with-jdbc
For now I like most this workaround which also supports indexes:
CREATE FUNCTION exist_inline (hstore, text) RETURNS bool AS $$ SELECT $1 ? $2; $$ LANGUAGE sql;
You can use this query to find the function backing an operator in PostgreSQL like this. In your example:
SELECT
oprname,
oprcode || '(' || format_type(oprleft, NULL::integer) || ', '
|| format_type(oprright, NULL::integer) || ')' AS function
FROM pg_operator
WHERE oprname LIKE '?%'
AND (SELECT oid FROM pg_type WHERE typname = 'hstore') IN (oprleft, oprright);
This produces:
|oprname|function |
|-------|--------------------------|
|? |exist(hstore, text) |
|?| |exists_any(hstore, text[])|
|?& |exists_all(hstore, text[])|
See also a related question about using JSON operators containing ?. Note that the function usage may not profit from the same indexing capability when using a GIN index on your HSTORE column.
If you'd like to add multiple key-value pairs using PreparedStatement then you can do:
PreparedStatement ps = c.prepareStatement(
"insert into xyz(id, data) values(?, hstore(?, ?))");
ps.setLong(1, 23456L);
ps.setArray(2, c.createArrayOf("text", new String[]{"name", "city"}));
ps.setArray(3, c.createArrayOf("text", new String[]{"Duke", "Valley"}));
This will insert: 23456, 'name=>Duke, city=>Valley'