I'm using Spring Boot 1.5.2 and the following #Query:
#Query(value = "SELECT m FROM Message m WHERE m.from.userId = :myId OR m.to.userId = :myId GROUP BY m.from.userId, m.to.userId ORDER BY m.date DESC")
List<Message> chatOverview(#Param("myId") final Long myUserId);
The intention of the query is to create a chat messenger overview, where you see the last message of each conversation you had. It works fine for me in dev, but in production (newer MySQL database version) I get this error:
java.sql.SQLSyntaxErrorException: Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'message0_.message_id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
I read in this thread what the reason for this change was, however I couldn't find a way to fix this with JPA / Spring. I cannot change any settings in the production MySQL database and I would like to avoid any upgrading in Spring either. How can I fix my query?
Here is the definition and purpose of the GROUP BY (see section 4.7) clause:
The GROUP BY construct enables the aggregation of result values according to a set of properties.
That means it is used only if you're aggregating (sum, avg, max, min, ...) the value(s) of a field(s). But in your case I don't see any aggregation function. So just remove the GROUP BY clause and everything should be fine:
SELECT m FROM Message m WHERE m.from.userId = :myId OR m.to.userId = :myId ORDER BY m.date DESC
Grouping on userId doesn't make sense too because all the entities returned by this query will have the same value for this field.
We are dealing with sybase database in core java code. We are using org.eobjects.metamodel.DataContext to parse query.
String sCol[]=table.getColumnNames();
Query query=dataContext.query().from(table.getName()).select(sCol).toQuery();
return new QueryIterator(dataContext.executeQuery(query).iterator());
But it executing query. Same code working fine with Oracle database to parse and execute query.
Some of query example generated are :
select City.CityName from ownername.City
select City.CityName from City
select CityName from ownername.City
select CityName from City
select ownername.City.CityName from ownername.City
SELECT "City"."CityName" FROM ownername."City"
select * from ownername.City
No any of above query executed. We are getting these errors :
Not capable of parsing FROM token: "ownername"."City"
Could not execute query: The column prefix '"City"' does not match with a table name or alias name used in the query. Either the table is not specified in the FROM clause or it has a correlation name which must be used instead.
Not capable of parsing SELECT token: ownername.City.CityName
How can we execute query using metamodel wih SYBASE database OR is there any other way to execute sybase queries?
Oracle (and Microsoft) use a schema logical construct that Sybase ASE does not. In SAP/Sybase ASE, all tables and columns in a database are in the same schema. It is possible to users to have their own objects in the database though, so there is the possibility of imitating some of the schema behavior using user ownership, but it would require an extra level of effort.
For Sybase the proper query syntax would be:
SELECT [ Col1, Col2 | * ]
FROM [dbName].[ownerName.]TABLE
In your case
SELECT CityName
FROM dbName.ownername.City
In Sybase ASE, it's typically best practice to have all objects owned by 'dbo', so in that case you can omit the owner from the query:
SELECT CityName
FROM dbName..City
Full query syntax and information can be found in the Query Section of the Transact SQL Users Guide in the documentation.
The error messages you're getting are coming from MetaModel's query parser layer. It is searching for matching column and table names in the metadata of your database before it's even firing the query.
I notice that you're using namespace "org.eobjects.metamodel". You should upgrade to Apache MetaModel ("org.apache.metamodel") if possible since a lot has been improved in MetaModel since it's introduction into Apache. Including a lot of query parser improvements.
While running the below query to get the latest message with the latest data using the createdOn column
i get the below error
select count(m) from MessageWorkFlowStatus mwfs1 where mwfs1.createdOn =(select max(createdOn) from MessageWorkFlowStatus mwfs2 where mwfs1.status= 'NEW' or mwfs1.status='IN PROGRESS')
The encapsulated expression is not a valid expression
Please let me know if i can run Query this way
First of all, count(m) is not correct. It should either be count(*) or count(mwfs1). Secondly, in your inner query, you are using status column from the outer query table (mswfs1) which is logically wrong. It should instead be mwfs2.status = 'NEW' or mwfs2.status = 'IN PROGRESS'.
I think your query should be:
select count(mwfs1)
from MessageWorkFlowStatus mwfs1
where mwfs1.createdOn = (
select max(createdOn)
from MessageWorkFlowStatus mwfs2
where mwfs2.status= 'NEW' or mwfs2.status='IN PROGRESS')
What SQL can be used to list the tables, and the rows within those tables in an SQLite database file - once I have attached it with the ATTACH command on the SQLite 3 command line tool?
There are a few steps to see the tables in an SQLite database:
List the tables in your database:
.tables
List how the table looks:
.schema tablename
Print the entire table:
SELECT * FROM tablename;
List all of the available SQLite prompt commands:
.help
The .tables, and .schema "helper" functions don't look into ATTACHed databases: they just query the SQLITE_MASTER table for the "main" database. Consequently, if you used
ATTACH some_file.db AS my_db;
then you need to do
SELECT name FROM my_db.sqlite_master WHERE type='table';
Note that temporary tables don't show up with .tables either: you have to list sqlite_temp_master for that:
SELECT name FROM sqlite_temp_master WHERE type='table';
It appears you need to go through the sqlite_master table, like this:
SELECT * FROM dbname.sqlite_master WHERE type='table';
And then manually go through each table with a SELECT or similar to look at the rows.
The .DUMP and .SCHEMA commands doesn't appear to see the database at all.
To show all tables, use
SELECT name FROM sqlite_master WHERE type = "table"
To show all rows, I guess you can iterate through all tables and just do a SELECT * on each one. But maybe a DUMP is what you're after?
Use .help to check for available commands.
.table
This command would show all tables under your current database.
There is a command available for this on the SQLite command line:
.tables ?PATTERN? List names of tables matching a LIKE pattern
Which converts to the following SQL:
SELECT name FROM sqlite_master
WHERE type IN ('table','view') AND name NOT LIKE 'sqlite_%'
UNION ALL
SELECT name FROM sqlite_temp_master
WHERE type IN ('table','view')
ORDER BY 1
To list the tables you can also do:
SELECT name FROM sqlite_master
WHERE type='table';
I use this query to get it:
SELECT name FROM sqlite_master WHERE type='table'
And to use in iOS:
NSString *aStrQuery=[NSString stringWithFormat:#"SELECT name FROM sqlite_master WHERE type='table'"];
Try PRAGMA table_info(table-name);
http://www.sqlite.org/pragma.html#schema
According to the documentation, the equivalent of MySQL's SHOW TABLES; is:
The ".tables" command is similar to setting list mode then executing
the following query:
SELECT name FROM sqlite_master
WHERE type IN ('table','view') AND name NOT LIKE 'sqlite_%'
UNION ALL
SELECT name FROM sqlite_temp_master
WHERE type IN ('table','view')
ORDER BY 1;
However, if you are checking if a single table exists (or to get its details), see LuizGeron's answer.
As of the latest versions of SQLite 3 you can issue:
.fullschema
to see all of your create statements.
The easiest way to do this is to open the database directly and use the .dump command, rather than attaching it after invoking the SQLite 3 shell tool.
So... (assume your OS command line prompt is $) instead of $sqlite3:
sqlite3> ATTACH database.sqlite as "attached"
From your OS command line, open the database directly:
$sqlite3 database.sqlite
sqlite3> .dump
Via a union all, combine all tables into one list.
select name
from sqlite_master
where type='table'
union all
select name
from sqlite_temp_master
where type='table'
Use:
import sqlite3
TABLE_LIST_QUERY = "SELECT * FROM sqlite_master where type='table'"
Use .da to see all databases - one is called 'main'.
Tables of this database can be seen by:
SELECT distinct tbl_name from sqlite_master order by 1;
The attached databases need prefixes you chose with AS in the statement ATTACH, e.g., aa (, bb, cc...) so:
SELECT distinct tbl_name from **aa.sqlite_master** order by 1;
Note that here you get the views as well. To exclude these add:
where type = 'table'
before ' order'
Since nobody has mentioned about the official reference of SQLite, I think it may be useful to refer to it under this heading:
https://www.sqlite.org/cli.html
You can manipulate your database using the commands described in this link. Besides, if you are using Windows OS and do not know where the command shell is, that is in the SQLite's site:
https://www.sqlite.org/download.html
After downloading it, click sqlite3.exe file to initialize the SQLite command shell. When it is initialized, by default this SQLite session is using an in-memory database, not a file on disk, and so all changes will be lost when the session exits. To use a persistent disk file as the database, enter the ".open ex1.db" command immediately after the terminal window starts up.
The example above causes the database file named "ex1.db" to be opened and used, and created if it does not previously exist. You might want to use a full pathname to ensure that the file is in the directory that you think it is in. Use forward-slashes as the directory separator character. In other words use "c:/work/ex1.db", not "c:\work\ex1.db".
To see all tables in the database you have previously chosen, type the command .tables as it is said in the above link.
If you work in Windows, I think it might be useful to move this sqlite.exe file to same folder with the other Python files. In this way, the Python file writes to and the SQLite shell reads from .db files are in the same path.
The ".schema" commando will list available tables and their rows, by showing you the statement used to create said tables:
sqlite> create table_a (id int, a int, b int);
sqlite> .schema table_a
CREATE TABLE table_a (id int, a int, b int);
Following on from one of my previous questions to do with method design I was advised to implemented my SQL queries as a parameterized query as opposed to a simple string.
I've never used parameterized queries before so I decided to start with something simple, take the following Select statement:
String select = "SELECT * FROM ? ";
PreparedStatement ps = connection.prepareStatement(select);
ps.setString(1, "person");
This gives me the following error: "[SQLITE_ERROR] SQL error or missing database (near "?": syntax error)"
I then tried a modified version which has additional criteria;
String select = "SELECT id FROM person WHERE name = ? ";
PreparedStatement ps = connection.prepareStatement(select);
ps.setString(1, "Yui");
This version works fine, in the my first example am I missing the point of parameterized queries or am I constructing them incorrectly?
Thanks!
Simply put, SQL binds can't bind tables, only where clause values. There are some under-the-hood technical reasons for this related to "compiling" prepared SQL statements. In general, parameterized queries was designed to make SQL more secure by preventing SQL injection and it had a side benefit of making queries more "modular" as well but not to the extent of being able to dynamically set a table name (since it's assumed you already know what the table is going to be).
If you want all rows from PERSON table, here is what you should do:
String select = "SELECT * FROM person";
PreparedStatement ps = connection.prepareStatement(select);
Variable binding does not dynamically bind table names as others mentioned above.
If you have the table name coming in to your method as a variable, you may construct the whole query as below:
String select = "SELECT * FROM " + varTableName;
PreparedStatement ps = connection.prepareStatement(select);
Parameterized queries are for querying field names - not the table name!
Prepared statements are still SQL and need to be constructed with the appropriate where clause; i.e. where x = y. One of their advantages is they are parsed by the RDMS when first seen, rather than every time they are sent, which speeds up subsequent executions of the same query with different bind values.