I have a column name "CustomerIDClass" and I need to find the table it's associated with within an entire Oracle database.
I've run this to determine the owner and name of the table where this column name appears:
select * from DBA_TAB_COLUMNS
where COLUMN_NAME LIKE '%CustomerIDClass%';
and I'm getting this response:
I don't have enough reputation to post the image, so here's the link: http://i.imgur.com/a7rcKoA.png
I have no idea how to access this (BIN$Csew==) table. When I try to use it as a table name I get errors or messages saying that no rows were returned.
My main goal here is to write a simple statement that lets me search the database for the "CustomerIDClass" and view the table that contains this column name.
This table is in the recycle bin. You have to issue FLASHBACK TABLE "Customer1"."BIN$Csew==$0" TO BEFORE DROP command, given you have the appropriate privileges.
Doc: http://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_9012.htm
Do note that in oracle the column names are stored in capital but you are using mixed case in your like statement therefore the select clause will not return any result
Try the below
select * from DBA_TAB_COLUMNS
where COLUMN_NAME LIKE '%CUSTOMERIDCLASS%';
Related
I have extracted list of names of tables in database using this sql query:
"SELECT table_name from information_schema.tables"
I got this list:
table_name
1 main_table
2 kp_table
3 ids_table
4 main_logs
Then i want to extract table ids_table:
"SELECT * from ids_table"
So desired result is to get that table, but i get this error:
Error: Failed to prepare query: ERROR: relation "ids_table" does not exist
LINE 1: SELECT * from ids_table
Why it happens? Why i get from first query its name, but then it tells me that it doesn't exist?
In this case, I would say that the most common issue is that you are looking at two different databases. That is probably not the cause in this case.
Another common possibility is that the schema is something unexpected, and you should be referencing the schema. For that, include the schema in the query:
select table_schema, table_name
from information_schema.tables
Another possibility are hidden characters, such as spaces. You can see if this is the problem by adding delimiters so check the names:
select '|' || table_name || '|'
from information_schema.tables
It looks like you are trying to select data from different schema, which by default owns by different user, but you have access to it. As this table is not created by user, which you are using for select * from ... , you must indicate schemas name before table name. Without schemas name it's trying to select date from users schema, but actually table are owned by completely different user.
How can I select the column name and table name from a SQL?
I tried something like this but it didn't work:
select column_name, table_name from (select * from users);
This might sound silly, but I have a list of different SQLs and I need to extract their columns and tables into a list. So some of the statements could me:
select username, password from users
select createdate from userlog
select * from dept
...
If I can select the column name and table name of a select statement, then I should get, say for the first statement, username and password for columns and users for table name. And createdate for column and userlog for table name in the second statement.
Then if it all works, I can then loop through the list of select statements and extract their column and table names.
The below query worked for Oracle database.
SELECT COLUMN_NAME,TABLE_NAME FROM ALL_TAB_COLUMNS
You can see more about information-schema
Edit:
You may try like this:
SELECT COLUMN_NAME,TABLE_NAME FROM ALL_TAB_COLUMNS
WHERE TABLE_NAME IN (SELECT ColumnName FROM users)
You need to parse the SQL statement so the SQL engine figures out the columns and datatypes of the columns that the statement returns.
How you do it best depends on what environment you are using. In some programming languages when you create a SqlPreparedStatement or OraCommand or whatever the object may be called, that object may have a metadata collection populated with column information after parsing.
If you are doing it in the database itself, parsing your statement with DBMS_SQL can get you the information you need. See Example 8 in the documentation at this link:
http://docs.oracle.com/database/121/ARPLS/d_sql.htm#ARPLS68205
--
Oh, and this gives you column names of the select statement. The table names I do not know of any way to get easily.
I had created the table with 200 columns and i had inserted data
Now i need to check that specific 100 columns in one row are filled or not,how can we check this using mysql query .the primary key is defined .please help me out how to resolve this.
select * from tablename where column1 != null or column2 != null ......
That is a lot of columns so at the risk of being mysql server version specific you can use the information schema to get the column names and then write a SQL procedure or something in your chosen shell / language that iterates over them performing a test.
select distinct COLUMN_NAME as 'Field', IS_NULLABLE from information_schema.columns where TABLE_SCHEMA="YourDatabase" and TABLE_NAME="YourTableName" and TABLE_NAME not like "%view%" escape '!' ;
The example above will tell you the column name as "Field" and tell you if it can hold a NULL. Having the field name may give you a better way of automating a field name specific test.
How can I add a column in an SQLite table if and only if the same column does not exist in the table?
Using ALTER TABLE I am able to create a new column but want to know how to check whether that column already exists in the table or not?
SQLite returns an error like "no such column: foo" if the table doesn't contain the column:
select foo from yourTable limit 1
Also you can get the create-table statement:
select sql from sqlite_master where tbl_name = 'YourTableName'
and then parse the result, looking for the column-name. I don't know of an elegant way to query the list of columns for a specified table, though one may exist.
Also if you attempt to do this:
alter table YourTable add column foo {column-def whatever it is}
you get an error from SQLite if the column already exists. You could trap that error too.
Finally you could do this:
select sql from sqlite_master
where tbl_name = 'YOURTABLE' and sql like '%"foo" CHAR%'; -- or whatever type
and if the specified table contains the column which is surrounded by double-quotes in the query, and with the type you have specified, you will get a result, otherwise an empty set. Specifying the datatype ensures that your LIKE substring match occurs on a column-name.
There's no way (that I know of) to do it all in a single SQLite query. You must use application code to manage the If/Elseness.
Check if table exists or not:
select count(*) from sqlite_master where type = 'table' and name = MyTable';
Check if column exists in table or now
pragma table_info(thumbnail);
However, a better approach may be explicit database schema updates based on schema versions your application maintains (e.g. specific alter table statement to go from schema version 1 to 2):
pragma user_version;
It seems like that it is impossible to do checking if the column not exists and addindg the new column in one command, because Sqlite don't support "IF NOT EXISTS" for column. "IF NOT EXISTS" works only on table.
Here is what I will do:
rev = ExecuteStatement("SELECT columnNamexx FROM tableNamexx limit 1;");
if(rev != SQLITE_OK){ // add col to table
ExecuteStatement("ALTER TABLE tableNamexx ADD COLUMN columnNamexx INTEGER DEFAULT 0;");
}
You can view the table columns by using '.schema tableName'
I'm using Oracle DB and I would like to write a SQL query that I could then call with JDBC. I'm not very familiar with SQL so if someone can help me, that could be great ! Here is the problem. I have a table MY_TABLE wich contains a list of another tables, and I would like to keep only the nonempty tables and those that their names start by a particular string.
The query I wrote is the following :
select TABLE_NAME
from MY_TABLE
where TABLE_NAME like '%myString%'
and (select count(*) from TABLE_NAME where rownum=1)<>0
order by TABLE_NAME;`
The problem comes from the second SELECT, but I don't know how can I do to use the TABLE_NAME value.
Does someone have an idea ?
Thanks.
[Added from comments]
Actually, I need to test the V$ views contained in the ALL_CATALOG table. But if I can find another table where all these views are contained too and with a NUM_ROWS column too, it would be perfect !
Standard versions of SQL do not allow you to replace 'structural elements' of the query, such as table name or column name, with variable values or place-holders.
There are a few ways to approach this.
Generate a separate SQL statement for each table name listed in MY_TABLE, and execute each in turn. Brute force, but effective.
Interrogate the system catalog directly.
Investigate whether there are JDBC metadata operations that allow you to find out about the number of rows in a table without being tied to the system catalog of the specific DBMS you are using.
Can you use oracle view USER_TABLES? then query will be much easier
select TABLE_NAME
from USER_TABLES
where TABLE_NAME like '%myString%'
and Num_ROWS > 0
order by TABLE_NAME;`