I would like to ask , is that got possible to change the table name just by using the TABLE PARAMETER setting? but the column name consists in the both table are the same.
eg:
table 1(dailyregistration)
table 2(dayreg)
P.S: both table got same column name, just the table name had change to (dayreg)
select * from ????????
I'm not too sure what you mean by TABLE PARAMETER, but it is not possible to use a Crystal parameter as one of the tables in the report's source. You can only achieve this effect by either writing your own application to set the data location to the one you want, or by using a stored procedure containing dynamic SQL and the table name as a parameter.
Related
Is it possible to dynamically select a table by name?
For example I have a table, and every time records are uploaded to it a backup is created first with the date appended to the table name.
table_20191108
table_20191109
table_20191110
table_20191111
What I would like to do is basically write some type of dynamic sql that always
select * from table_MAXDATE
I would like to do this so I can compare table to the most recent backup (e.g. table_20191111) in order to see what changed between the two tables.
haven't tried anything specific yet.
I'm a real beginner when it comes to SQL and I'm currently trying to build a database using postgres. I have a lot of data I want to put into my database in JSON files, but I have trouble converting it into tables. The JSON is nested and contains many variables, but the behavior of jsonb_populate_record allows me to ignore the structure I don't want to deal with right now. So far I have:
CREATE TABLE raw (records JSONB);
COPY raw from 'home/myuser/mydocuments/mydata/data.txt'
create type jsonb_type as (time text, id numeric);
create table test as (
select jsonb_populate_record(null::jsonb_type, raw.records) from raw;
When running the select statement only (without the create table) the data looks great in the GUI I use (DBeaver). However it does not seem to be an actual table as I cannot run select statements like
select time from test;
or similar. The column in my table 'test' also is called 'jsonb_populate_record(jsonb_type)' in the GUI, so something seems to be going wrong there. I do not know how to fix it, I've read about people using lateral joins when using json_populate_record, but due to my limited SQL knowledge I can't understand or replicate what they are doing.
jsonb_populate_record() returns a single column (which is a record).
If you want to get multiple columns, you need to expand the record:
create table test
as
select (jsonb_populate_record(null::jsonb_type, raw.records)).*
from raw;
A "record" is a a data type (that's why you need create type to create one) but one that can contain multiple fields. So if you have a column in a table (or a result) that column in turn contains the fields of that record type. The * then expands the fields in that record.
Is there any way to create a postgis table with existing style from layer_styles table? Say for example i have so many styles stored in layer_styles table. I need to assign one of the style from layer_styles table to the new table which i am going to create. Can that be done using postgresql during table creation using sql command?
You need to identify the layer IDs of interest (or name, or any column you want) and to create the new table using this data+structure. However using the style in this secondary table may not be that easy
create table public.layer_styles_2 as
(select * from public.layer_styles where id in (2,3));
I've noticed that while I can use %dictionary.compiledclass to get a table with schema names and table names, which allow querying for their existence, I cannot do the same for columns. I have yet to find the command that allows verifying whether a column exists or not, or retrieving numerous column names using LIKE "prefix%".
Is there even such a thing? Or an alternative?
You can use %Dictionary.CompiledProperty table and SqlFieldName column of that table.
For example to find out tables that have column 'ColumnName' you can use this query:
select parent->SqlTableName
from %dictionary.compiledproperty
where SqlFieldName='ColumnName'
Execute this Query :
select * from %dictionary.compiledproperty Where parent='TableName' and SqlFieldName='ColumnName'
Check Row Count value ,0 not exist
I have to display a column name from a select query from table, e,g, 'Column 1' is stored in table table1, I want to display 'Column 1' as column name. I cannot hardcode 'Column 1' as it might be unknown when the code is developed.
Column 1 Column 2
a b
Any idea?
Update
It allows user to define column name.
It has to generate via T SQL
Add alias as a separate column or use dynamic SQL
This doesn't make sense because doing you should know what the column is called: you don't store information about columns and build queries on your own metadata
IF you don't know the name of the column at design time, then use a resource file or similar in the presentation layer to hold the value that you will display as the label for column1. It should be noted, however, you are going to have a very hard time writing any code if you don't know the names of the columns in your database, unless you are select * on everything.
Column names are fairly restricted and should be named with the SQL admin and application developer as the user of the names. It is not the intent of a column name to be descriptor for the end user interface.
Select dbColumn1 as [Customer Name] from tableMain
Even that is not a good practice and then user input is part of the TSQL and you are opening yourself up to SQL injection attacks and it is just not very good control on you query. A better practice is to pass parameters.