information-schema

I'm performing some database clean up and have noticed that there are a lot of columns that have both empty strings and NULL values in various columns. Is it possible to write an SQL statement to update the empty strings to NULL for each column of each table in my database, except for the ones that do not allow NULL's? I've looked at the information_schema.COLUMNS table and think that this might be the place to start. It's not possible to do this with one simple SQL statement. But you can do it using one statement for each column. UPDATE TABLE SET COLUMN = NULL WHERE LENGTH(COLUMN) = 0 or, if

I have a table named rabbits. I am trying to find the average row length in my table. I tried this query: SELECT AVG_ROW_LENGTH(rabbits) but it doesn't work. Redbeard011010 My Googling has indicated that AVG_ROW_LENGTH is actually a column in information_schema.tables. You'll want to try something like this, I think: SELECT AVG_ROW_LENGTH FROM information_schema.tables WHERE TABLE_NAME = 'rabbits'; You may also need to specify the database name by adding "AND TABLE_SCHEMA = 'databasename';" if you have more than one database with a rabbits table. Hope this helps! You can't SELECT that, try

I have a series of stored procedures that select data from a db. I have a role (cctc_reader) that has execute permissions granted on the procedures. One of the procedure calls another stored procedure called recControl_system_option which in turn queries Information_schema.columns . The problem is that in this proc the query select column_name from information_schema.columns where table_name = 'recControl_manager' does not return any records. cctc_reader has grant permissions on: each select proc recControl_system_option so in theory this should work. I have no problems when run under dbo. If

I need to determine what privileges are currently granted for some materialized views in my database. The query to do this for a table or standard view is pretty straight forward: SELECT grantee, string_agg(privilege_type, ', ') AS privileges FROM information_schema.table_privileges WHERE table_schema = 'some_schema' AND table_name = 'some_table' GROUP by grantee; That said, there doesn't seem to be an analogous table for materialized views. Where does PostgreSQL store this information? In Postgres system catalogs are the basic set of complete information about the installation and databases.

I had an assignment for each table to count nullable columns. Easy: SELECT table_name, count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE is_nullable='NO' GROUP BY table_name; Now I have to modify this to count "columns that have property "NOT NULL"". Will the following code do this or will it just check weather column name is not null? CREATE TEMP TABLE A AS SELECT DISTINCT column_name, table_name AS name FROM INFORMATION_SCHEMA.COLUMNS WHERE column_name IS NOT NULL GROUP BY table_name, column_name; SELECT name, count(*) FROM A GROUP BY name; If no... Any advices? No. This query SELECT DISTINCT