Our data model in one of the rows looks like:
productName.productDescriptor.productMetadata
There is not a lot of data in this table. Is there a "good" way to parse that data, like get all the
Products where productDescriptor equals <MyDescriptor>
?
You can use a query like this:
var result = myRows.Where(x => x.myColumn.Contains("." + productDescriptor + "."));
If the components of your strings contain the separator period, this will not work.
Related
How do I get unique values of one column based on another column using the query?
I tried using
(double)selectFrom(tasks).where(tasks.tasks_type.eq()).uniqueResult(tasks.task_cycle_time_hr);
I want to automate this and make sure that all the values of task_type are being read and a unique value for each of the tasks_type is being returned!
For all the values in the column task_type, I require a unique value from the column task_cycle_time_hr.
I don't really understand why you're trying to do this in one query.
If you want to get the cycle time (task_cycle_time_hr column) for each task type (tasks_type column), just do queries in a loop for each possible tasks_type value. If you don't know those a priori, do queries for each value returned by a query of the task type values, which would look something like
for (String taskType : selectFrom(tasks).list(tasks.tasks_type)) {
double cycleTime = (double) selectFrom(tasks)
.where(db_table.tasks_type.eq(taskType))
.firstResult(tasks.task_cycle_time_hr);
traceln("Task type " + taskType + ", cycle time " + cycleTime);
}
But this just amounts to querying all rows and reading the task type and cycle time values from each, so you wouldn't normally do it like this: you'd just have a single query looping through all the full rows instead...
List<Tuple> rows = selectFrom(tasks).list();
for (Tuple row : rows) {
traceln("Task type " +
row.get(tasks.tasks_type) + ", cycle time " +
row.get(tasks.task_cycle_time_hr));
}
NB: I assume you don't have any rows with duplicate task types because then the whole exercise doesn't make sense unless you want only the first row for each task type value, or want some kind of aggregate (e.g., sum) of the cycle time values for each given task type. You were trying to use uniqueResult, which may mean you want to get a value if there is exactly one row (for a given task type) and 'no result otherwise', but uniqueResult throws an exception (errors) if there isn't exactly one row (so you can't use that directly like that). In that case one way (there are others, some probably slightly better) would be to do a count first to check; e.g. something like
for (String taskType : selectFrom(tasks).list(tasks.tasks_type)) {
int rowCount = (int) selectFrom(tasks)
.where(db_table.task.eq(taskType))
.count();
if (rowCount == 1) {
double cycleTime = (double) selectFrom(tasks)
.where(db_table.tasks_type.eq(taskType))
.firstResult(tasks.task_cycle_time_hr);
traceln("Task type " + taskType + ", unique cycle time " + cycleTime);
}
}
Import your excel sheet into the AnyLogi internal DB and then make use of the DB wizard that will take you step by step to write the code to retrieve the data you want
(double) selectFrom(data)
.where(data.tasks.eq("T1"))
.firstResult(data.task_cycle_time_hr)
How can I concatenate a string inside of a concatenated jsonb object in postgresql? In other words, I am using the JSONb concatenate operator as well as the text concatenate operator in the same query and running into trouble.
Or... if there is a totally different query I should be executing, I'd appreciate hearing suggestions. The goal is to update a row containing a jsonb column. We don't want to overwrite existing key value pairs in the jsonb column that are not provided in the query and we also want to update multiple rows at once.
My query:
update contacts as c set data = data || '{"geomatch": "MATCH","latitude":'||v.latitude||'}'
from (values (16247746,40.814140),
(16247747,20.900840),
(16247748,20.890570)) as v(contact_id,latitude) where c.contact_id = v.contact_id
The Error:
ERROR: invalid input syntax for type json
LINE 85: update contacts as c set data = data || '{"geomatch": "MATCH...
^
DETAIL: The input string ended unexpectedly.
CONTEXT: JSON data, line 1: {"geomatch": "MATCH","latitude":
SQL state: 22P02
Character: 4573
You might be looking for
SET data = data || ('{"geomatch": "MATCH","latitude":'||v.latitude||'}')::jsonb
-- ^^ jsonb ^^ text ^^ text
but that's not how one should build JSON objects - that v.latitude might not be a valid JSON literal, or even contain some injection like "", "otherKey": "oops". (Admittedly, in your example you control the values, and they're numbers so it might be fine, but it's still a bad practice). Instead, use jsonb_build_object:
SET data = data || jsonb_build_object('geomatch', 'MATCH', 'latitude', v.latitude)
There are two problems. The first is operator precedence preventing your concatenation of a jsonb object to what is read a text object. The second is that the concatenation of text pieces requires a cast to jsonb.
This should work:
update contacts as c
set data = data || ('{"geomatch": "MATCH","latitude":'||v.latitude||'}')::jsonb
from (values (16247746,40.814140),
(16247747,20.900840),
(16247748,20.890570)) as v(contact_id,latitude)
where c.contact_id = v.contact_id
;
In a SQL Server database I have a column of decimal datatype defined something like this:
CREATE TABLE MyTable
(
Id INT,
Number DECIMAL(9, 4)
)
I use Entity Framework and I would like to return column Number converted to a string with only the digits right of the decimal separator that are actually needed. A strict constraint is that a result must be an IQueryable.
So my query is:
IQueryable queryable = (
from myTable in MyDatabase.NyTable
select new
{
Id = myTable.Id,
Number = SqlFunctions.StringConvert(myTable.Number,9,4)
}
);
The problem with is that it always convert number to string with 4 decimals, even if they are 0.
Examples:
3 is converted to "3.0000"
1.2 is converted to "1.2000"
If I use other parameters for StringConvert i.e.
SqlFunctions.StringConvert(myTable.Number, 9, 2)
the results are also not OK:
0.375 gets rounded to 0.38.
StringConvert() function is translated into SQL Server function STR.
https://learn.microsoft.com/en-us/sql/t-sql/functions/str-transact-sql?view=sql-server-2017
This explains the weird results.
In the realm of Entity Framework and LINQ I was not able to find a working solution.
What I look for is something like C# function
String.Format("0.####", number)
but this cannot be used in a LINQ query.
In plain simple SQL I could write my query like this
SELECT
Id,
Number = CAST(CAST(Number AS REAL) AS VARCHAR(15))
FROM
MyTable
I have not managed to massage LINQ to produce query like that.
A workaround would be to forget doing this in LINQ, which is quite inflexible and messy thing, borderline on useless and just return type DECIMAL from database and do my formatting on a client side before displaying. But this is additional, unnecessary code and I would hate to di it that way if there perhaps is a simpler way via LINQ.
Is it possible to format numbers in LINQ queries?
I would absolutely return a decimal from he database and format it when needed. Possible directly after the query. But usually this is done at display time to take into account culture specific formatting from the the client.
var q =
(from myTable in MyDatabase.NyTable
select new
{
Id = myTable.Id,
Number = myTable.Number
})
.AsEnumerable()
.Select(x => new { Id = x.Id, Number = x.Number.ToString("G29") });
I have a List:hdtList which contain columns that represent the columns of a Hive table:
forecast_id bigint,period_year bigint,period_num bigint,period_name string,drm_org string,ledger_id bigint,currency_code string,source_system_name string,source_record_type string,gl_source_name string,gl_source_system_name string,year string
I have a List: partition_columns which contains two elements: source_system_name, period_year
Using the List: partition_columns, I am trying to match them and move the corresponding columns in List: hdtList to the end of it as below:
val (pc, notPc) = hdtList.partition(c => partition_columns.contains(c.takeWhile(x => x != ' ')))
But when I print them as: println(notPc.mkString(",") + "," + pc.mkString(","))
I see the output unordered as below:
forecast_id bigint,period_num bigint,period_name string,drm_org string,ledger_id bigint,currency_code string,source_record_type string,gl_source_name string,gl_source_system_name string,year string,period string,period_year bigint,source_system_name string
The columns period_year comes first and the source_system_name last. Is there anyway I can make data as below so that the order of columns in the List: partition_columns is maintained.
forecast_id bigint,period_num bigint,period_name string,drm_org string,ledger_id bigint,currency_code string,source_record_type string,gl_source_name string,gl_source_system_name string,year string,period string,source_system_name string,period_year bigint
I know there is an option to reverse a List but I'd like to learn if I can implement a collection that maintains that order of insert.
It doesn't matter which collections you use; you only use partition_columns to call contains which doesn't depend on its order, so how could it be maintained?
But your code does maintain order: it's just hdtList's.
Something like
// get is ugly, but safe here
val pc1 = partition_columns.map(x => pc.find(y => y.startsWith(x)).get)
after your code will give you desired order, though there's probably more efficient way to do it.
I want to search one of my tables using Entity Framework 5. I don't know how many words there are in the query, but I want to match all of them.
query = hello
SELECT * FROM [table] WHERE [column] LIKE '%hello%'
query = hello world
SELECT * FROM [table] WHERE [column] LIKE '%hello%' AND [column] LIKE '%world%'
I know the function PATINDEX , but it doesn't work good enough. Why? I'll show you:
SELECT * FROM person WHERE PATINDEX('%test%.com%', email)>0
will match "test#email.com", but if the search word are ordered the other way, it will not find this person:
SELECT * FROM person WHERE PATINDEX('%.com%test%', email)>0
What is the most efficient way to create this query using EF?
using linq to entities you can use .Contains to do the equivilant in SQL
table(x => x.column).Where(y => y.ColumnName).Contains("hello");
Sorry forgot the where clause that should work.
You can build the query in a foreach loop:
var words = new[] {"com", "test"};
var table = <your initial DbSet or ObjectSet>
foreach (var word in words)
{
string word1 = word; // prevent modified closure.
table = table.Where(x => x.column.Contains(word1));
}
var result = table.ToList(); // Enumerate the composed linq query.
The Contains function translates to LIKE with the search term enclosed in % characters.