第七章分层检索 语法： SELECT [LEVEL], column, expr... FROM table [WHERE condition(s)] [START WITH condition(s)] [CONNECT BY PRIOR condition(s)] ; 例如： SELECT employee_id, last_name, job_id, manager_id FROM employees START WITH employee_id = 101 CONNECT BY PRIOR manager_id = employee_id ; SELECT last_name||' reports to '|| PRIOR last_name "Walk Top Down" FROM employees START WITH last_name = 'King' CONNECT BY PRIOR employee_id = manager_id ; 第八章，正则表达式支持 REGEXP_LIKE: 语法：REGEXP_LIKE (srcstr, pattern [,match_option]) 例如： SELECT first_name, last_name FROM employees WHERE REGEXP_LIKE (first_name, '^Ste(v|ph)en$'); REGEXP_REPLACE 语法： REGEXP_REPLACE(srcstr, pattern [,replacestr [, position [, occurrence [, match_option]]]]) REGEXP_INSTR 语法： REGEXP_INSTR (srcstr, pattern [, position [, occurrence [, return_option [, match_option]]]]) 例如： SELECT street_address, REGEXP_INSTR(street_address,'[^[:alpha:]]') FROM locations WHERE REGEXP_INSTR(street_address,'[^[:alpha:]]')> 1; REGEXP_SUBSTR 语法： REGEXP_SUBSTR (srcstr, pattern [, position [, occurrence [, match_option]]]) 例如： SELECT REGEXP_SUBSTR(street_address , ' [^ ]+ ') "Road" FROM locations; 添加一个检查约束： ALTER TABLE emp8 ADD CONSTRAINT email_addr CHECK(REGEXP_LIKE(email,'@'))NOVALIDATE ;
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