练习了一下,
用时再慢慢看吧。
SHOW WARNINGS;
SELECT quote(text_fld) FROM string_tbl;
SELECT CONCAT(‘danke sch‘, CHAR(148), ‘n‘);
SELECT ASCII(‘ö‘);
SELECT LENGTH(char_fld) char_length FROM string_tbl;
SELECT POSITION(‘is‘ IN vchar_fld) FROM string_tbl;
SELECT (37 * 59) / (78 - (8 * 6));
SELECT MOD(10,4);
SELECT POW(2,10) kilobyte, POW(2,20) megabyte, -> POW(2,30) gigabyte, POW(2,40) terabyte;
SELECT ROUND(72.0909, 1), ROUND(72.0909, 2), ROUND(72.0909, 3);
SELECT account_id, SIGN(avail_balance), ABS(avail_balance) -> FROM account;
SELECT @@global.time_zone, @@session.time_zone;
SELECT CAST(‘2008-09-17 15:30:00‘ AS DATETIME);
SELECT CAST(‘2008-09-17‘ AS DATE) date_field, -> CAST(‘108:17:57‘ AS TIME) time_field;
SELECT CURRENT_DATE(), CURRENT_TIME(), CURRENT_TIMESTAMP();
SELECT DATE_ADD(CURRENT_DATE(), INTERVAL 5 DAY);
SELECT LAST_DAY(‘2008-09-17‘);
SELECT DAYNAME(‘2008-09-18‘);
SELECT EXTRACT(YEAR FROM ‘2008-09-18 22:19:05‘);
SELECT DATEDIFF(‘2009-09-03‘, ‘2009-06-24‘);
SELECT CAST(‘1456328‘ AS SIGNED INTEGER);
SELECT CAST(‘999ABC111‘ AS UNSIGNED INTEGER);
时间: 2024-11-02 23:27:31