Somehow when doing an import of data into mysql using a multi-row insert with execute() function, there were many rows added with the string NULL for some columns.
How can I convert those NULL strings into MySQL NULL values so that I can check for empty values using is_null() in php when displaying data.
How can I avoid this problem? I was using the quote() function for each piece of data. Was that the problem using quote on empty fields? I was importing a csv file.
thank you
To insert an SQL NULL or any other expression, you can use a Zend_Db_Expr object. Even if you use quote(), ZF passes these objects through unquoted.
$null = new Zend_Db_Expr("NULL");
$table = new MyTable();
$table->insert(123, "abc", $null);
Note that because use of Zend_Db_Expr bypasses both quoting and parameterization, you're responsible for protecting against SQL injection.
This is tangential to your question, but consider LOAD DATA INFILE if you're bulk-loading a CSV file. It can be 20x faster than even using multi-row INSERT.
Related
I'm converting the SQL server to db2..
I need a solution for stuff and for xml path
Ex
Select stuff(select something
from table name
Where condition
For xml path(''),1,1,'')
Pls convert this into db2.
Your code is an old school XML "trick" to convert multiple values to a single string. (Often comma separated but in this case space separated.) Since those days DB2 (and the sql standards) have added a new function called listagg which is designed to solve this exact problem:
Select listagg(something,' ')
from table name
Where condition
db2 docs -
https://www.ibm.com/support/knowledgecenter/en/SSEPEK_12.0.0/sqlref/src/tpc/db2z_bif_listagg.html
https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/db2/rbafzcollistagg.htm
I've got a table TABLE that contains a jsonb column named tags. The tags element in each row may or may not contain a field called group. My goal is to group by tags.group for all rows where tags contains a group field. Like the following postgres query:
select tags->>'group' as group, sum(n) as sum
from TABLE
where tags ? 'group'
group by tags->>'group';
I'm trying to turn it into JOOQ and cannot find out how to express the where tags ? 'group' condition.
For example,
val selectGroup = DSL.field("{0}->>'{1}'", String::class.java, TABLE.TAGS, "group")
dsl().select(selectGroup, DSL.sum(TABLE.N))
.from(TABLE)
.where(TABLE.TAGS.contains('group'))
.groupBy(selectGroup)
This is equivalent to testing contains condition #> in postgres. But I need to do exists condition ?. How can I express that in JOOQ?
There are two things worth mentioning here:
The ? operator in JDBC
Unfortunately, there's no good solution to this as ? is currently strictly limited to be used as a bind variable placeholder in the PostgreSQL JDBC driver. So, even if you could find a way to send that character to the server through jOOQ, the JDBC driver would still misinterpret it.
A workaround is documented in this Stack Overflow question.
Plain SQL and string literals
When you're using the plain SQL templating language in jOOQ, beware that there is a parser that will parse certain tokens of your string, including e.g. comments and string literals. This means that your usage of...
DSL.field("{0}->>'{1}'", String::class.java, TABLE.TAGS, "group")
is incorrect, as '{1}' will be parsed as a string literal and sent to the server as is. If you want to use a variable string literal, do this instead:
DSL.field("{0}->>{1}", String::class.java, TABLE.TAGS, DSL.inline("group"))
See also DSL.inline()
I have a postgres query with one input parameter of type varchar.
value of that parameter is used in where clause.
Till now only single value was sent to query but now we need to send multiple values such that they can be used with IN clause.
Earlier
value='abc'.
where data=value.//current usage
now
value='abc,def,ghk'.
where data in (value)//intended usage
I tried many ways i.e. providing value as
value='abc','def','ghk'
Or
value="abc","def","ghk" etc.
But none is working and query is not returning any result though there are some matching data available. If I provide the values directly in IN clause, I am seeing the data.
I think I should somehow split the parameter which is comma separated string into multiple values, but I am not sure how I can do that.
Please note its Postgres DB.
You can try to split input string into an array. Something like that:
where data = ANY(string_to_array('abc,def,ghk',','))
I have a CLOB(2000000) field in a db2 (v10) database, and I would like to run a simple UPDATE query on it to replace each occurances of "foo" to "baaz".
Since the contents of the field is more then 32k, I get the following error:
"{some char data from field}" is too long.. SQLCODE=-433, SQLSTATE=22001
How can I replace the values?
UPDATE:
The query was the following (changed UPDATE into SELECT for easier testing):
SELECT REPLACE(my_clob_column, 'foo', 'baaz') FROM my_table WHERE id = 10726
UPDATE 2
As mustaccio pointed out, REPLACE does not work on CLOB fields (or at least not without doing a cast to VARCHAR on the data entered - which in my case is not possible since the size of the data is more than 32k) - the question is about finding an alternative way to acchive the REPLACE functionallity for CLOB fields.
Thanks,
krisy
Finally, since I have found no way to this by an SQL query, I ended up exporting the table, editing its lob content in Notepad++, and importing the table back again.
Not sure if this applies to your case: There are 2 different REPLACE functions offered by DB2, SYSIBM.REPLACE and SYSFUN.REPLACE. The version of REPLACE in SYSFUN accepts CLOBs and supports values up to 1 MByte. In case your values are longer than you would need to write your own (SQL-based?) function.
BTW: You can check function resolution by executing "values(current path)"
I run this
db2 "IMPORT FROM C:\my.csv OF DEL MODIFIED BY COLDEL, LOBSINFILE DATEFORMAT=\"D/MM/YYYY\" SKIPCOUNT 1 REPLACE INTO scratch.table_name"
However some of my rows have a empty date field so I get this error
SQL3191N which begins with """" does not match the user specified DATEFORMAT, TIMEFORMAT, or TIMESTAMPFORMAT. The row will be rejected.
My CSV file looks like this
"XX","25/10/1985"
"YY",""
"ZZ","25/10/1985"
I realise if I insert charater instead of a blank string I could use NULL INDICATORS paramater.
However I do not have access to change the CSV file. Is there a way to ignore import a blank string as a null?
This is an error in your input file. DB2 differentiates between a NULL and a zero-length string. If you need to have NULL dates, a NULL would have no quotes at all, like:
"AA",
If you can't change the format of the input file, you have 2 options:
Insert your data into a staging table (changing the DATE column to a char) and then using SQL to populate the ultimate target table
Write a program to parse ("fix") the input file and then import the resulting fixed data. You can often do this without having to write the entire file out to disk – your program could write to a named pipe, and the DB2 IMPORT (and LOAD) utility is capable of reading from named pipes.
I'm not aware of anything. Yes, ideally that date field should be null.
Probably the best thing to do would be load the data into a scratch/temp table where that isn't a date column - just leave it as character data (it looks like you're already using a scratch table anyways). It should be trivial after that to use a CASE statement to transform the information into a null date if the value is blank, when doing your INSERT to the real table.