PHP：使用REGEX从任何查询中获取表名（选择，更新，插入，删除）

Question

Consider these three sql statements:

SELECT * FROM Users;

DELETE FROM Users WHERE id =1;

UPDATE Users SET name='test' WHERE id= 1;

Now im not very good at REGEX, but i want to get the table name from the postgres query. Could someone possibly create one for me with a little explanation.

Thanks,

Answer 1

For those simple queries, the following will suffice. However, note that it will not work when there are subqueries, or UPDATE statements do not start with the word UPDATE (such as cases when there are comments in the header, or the UPDATE is a part of a CTE).

WITH stmts(_sql) AS (values ('SELECT * FROM Users1;'::text), ('DELETE FROM Users2 WHERE id =1;'), ('UPDATE Users3 SET name=''test'' WHERE id= 1;'))
SELECT _sql, (regexp_matches(_sql, CASE WHEN _sql ~* '^\s*update' THEN '^\s*update' ELSE 'from' END||'\s+([^\s;]+)', 'im'))[1]
FROM stmts

Tablename is obtained from either what follows to UPDATE as a first statement, or immediately after the first FROM statement. Matches are case insensitive (i) and multiline (m).