mariadb/mysql-test/main/create_drop_trigger.test

CREATE DATABASE db1;
USE db1;
CREATE TABLE t1 (val INT);
CREATE TRIGGER IF NOT EXISTS val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val;
SET @sum=0;
INSERT INTO t1 VALUES (10), (20), (30);
SELECT @sum;

CREATE TRIGGER IF NOT EXISTS val_sum_new BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val;

CREATE TRIGGER IF NOT EXISTS val_sum AFTER INSERT ON t1 FOR EACH ROW SET @sum = @sum + 1 + NEW.val;

--error ER_WRONG_USAGE
CREATE OR REPLACE TRIGGER IF NOT EXISTS val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 2 + NEW.val;
SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';

CREATE OR REPLACE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 3 + NEW.val;
SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';

--error ER_TRG_ALREADY_EXISTS
CREATE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 4 + NEW.val;
SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';

--echo # Clearing up
DROP TRIGGER IF EXISTS val_sum;
SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
DROP TRIGGER IF EXISTS val_sum;

DROP TABLE t1;
DROP DATABASE db1;