I tried to EXPLAIN ANALYZE the above query, but execution took over 2hrs so I killed it. The query is as follows: SELECT DROP TABLE IF EXISTS. " -> Hash (cost=6900.01 rows=3763601 width=38)" PostgreSQL stores all the tables and the table metadata on its record table called pgtable. selfintersects (pargeom) returns X rows with 4 columns/attributes, - where X corresponds to number. " -> Seq Scan on name2phoneme (cost=48.16 rows=18062616 width=38)" create or replace function removevertices (pargeom geometry) returns geometry as DECLARE cnt int BEGIN drop table if exists invalidpnts create temp table invalidpnts as select from selfintersects (pargeom) - calls other function. In the below example, we have deleted a single row from the student table are as follows. We have deleting a single row from the table using the where clause. DROP TABLE always removes any indexes, rules, triggers, and constraints that. Delete the statement with one condition We can delete single rows in PostgreSQL. " Hash Cond: ((name2phoneme.name_id = d.name_id) AND (name2phoneme.phoneme_id = d.phoneme_id))" To empty a table of rows without destroying the table, use DELETE or TRUNCATE. Here's the output of EXPLAIN of the above query: "Delete on name2phoneme (cost=1548580.46 rows=6449114 width=12)" The "target" table originally contains a little over 18M rows, while the delta table contains about 3.7M rows (that are to be deleted from the target). REFERENCES phoneme (phoneme_id) MATCH SIMPLE You can disable the display of those notices trough the property clientminmessages which controls the minimum level of messages returned to the client. This is the layout of both tables (whith the exception that the "delta" schema only has primary keys and no foreign keys) CREATE TABLE name2phonemeĬONSTRAINT pk_name2phoneme PRIMARY KEY (name_id, phoneme_id),ĬONSTRAINT fk_name2phoneme_name_id_2_name FOREIGN KEY (name_id)ĬONSTRAINT fk_name2phoneme_phoneme_id_2_phoneme FOREIGN KEY (phoneme_id) 1 Answer Sorted by: 9 The 'warning' is in fact a 'notice'. Here's an example query: DELETE FROM "target".name2phonemeĪND name2phoneme.PHONEME_ID = d.PHONEME_ID I have tried this using the DELETE FROM WHERE EXISTS approach, but that seems incredibly slow. I now want to delete all rows that appear in the delta schema from the target schema. I have a schema ,say "target" containing tables that all have an equivalent table (identical columns & primary keys) in another one, say "delta". How to delete a row in MySQL if the condition is met. Phpmyadmin Function Delete row if exists in other table. I'm having trouble with slow delete queries. When youre deleting rows from a table, you dont need to use IF EXISTS - youre using a WHERE clause, so if it exists - it will be deleted.
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