جمله update معقده

CREATE TABLE test AS
SELECT table_name, CAST('' AS VARCHAR2(30)) AS lower_name
FROM user_tables;
desc test
SELECT *
FROM test
WHERE table_name LIKE '%A%';
SELECT *FROM testWHERE table_name NOT LIKE '%A%';
-- this is not a good thing ...
UPDATE test t SET lower_name = (SELECT DISTINCT LOWER(table_name)
FROM user_tables u
WHERE u.table_name = t.table_name
AND u.table_name LIKE '%A%');
-- look at the number of rows updated
SELECT * FROM test;-- neither is this
UPDATE test t SET lower_name = (
SELECT DISTINCT LOWER(table_name)
FROM user_tables u
WHERE u.table_name = t.table_name
AND u.table_name NOT LIKE '%A%');
SELECT * FROM test; UPDATE testt
SET lower_nam = (SELECT DISTINCT LOWER(table_name)
FROM user_tables u WHERE u.table_name = t.table_name
AND u.table_name LIKE '%A%')WHERE t.table_name LIKE '%A%';
SELECT * FROM test;