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TO_CHAR
TO_CHAR 将时间戳或数值表达式转换为字符串数据格式。
语法
TO_CHAR (timestamp_expression | numeric_expression , 'format')
参数
返回类型
VARCHAR
示例
以下示例将时间戳转换为一个具有日期和时间的值，格式为月份名称填充为九个字符、星期几的名称和当月的日期编号。
select to_char(timestamp '2009-12-31 23:15:59', 'MONTH-DY-DD-YYYY HH12:MIPM'); to_char ------------------------- DECEMBER -THU-31-2009 11:15PM
以下示例将时间戳转换为具有这一年中日期编号的值。
select to_char(timestamp '2009-12-31 23:15:59', 'DDD'); to_char ------------------------- 365
以下示例将时间戳转换为这一周的 ISO 日期编号。
select to_char(timestamp '2022-05-16 23:15:59', 'ID'); to_char ------------------------- 1
以下示例从日期中提取月份名称。
select to_char(date '2009-12-31', 'MONTH'); to_char ------------------------- DECEMBER
以下示例将 EVENT 表中的每个 STARTTIME 值转换为由小时、分钟和秒组成的字符串。
select to_char(starttime, 'HH12:MI:SS') from event where eventid between 1 and 5 order by eventid; to_char ---------- 02:30:00 08:00:00 02:30:00 02:30:00 07:00:00 (5 rows)
以下示例将整个时间戳值转换为不同的格式。
select starttime, to_char(starttime, 'MON-DD-YYYY HH12:MIPM') from event where eventid=1; starttime | to_char ---------------------+--------------------- 2008-01-25 14:30:00 | JAN-25-2008 02:30PM (1 row)
以下示例将时间戳文本转换为字符串。
select to_char(timestamp '2009-12-31 23:15:59','HH24:MI:SS'); to_char ---------- 23:15:59 (1 row)
以下示例将一个数字转换为末尾带负号的字符串。
select to_char(-125.8, '999D99S'); to_char --------- 125.80- (1 row)
以下示例将一个数字转换为带货币符号的字符串。
select to_char(-125.88, '$S999D99'); to_char --------- $-125.88 (1 row)
以下示例将一个数字转换为用尖括号将负数括起来的字符串。
select to_char(-125.88, '$999D99PR'); to_char --------- $<125.88> (1 row)
以下示例将一个数字转换为罗马数字字符串。
select to_char(125, 'RN'); to_char --------- CXXV (1 row)
以下示例显示一周中的某天。
SELECT to_char(current_timestamp, 'FMDay, FMDD HH12:MI:SS');to_char ----------------------- Wednesday, 31 09:34:26
以下示例显示数字的序数后缀。
SELECT to_char(482, '999th');to_char ----------------------- 482nd
以下示例将销售表中支付的价格减去佣金。然后将差值四舍五入并转换为罗马数字，如to_char列中所示：
select salesid, pricepaid, commission, (pricepaid - commission) as difference, to_char(pricepaid - commission, 'rn') from sales group by sales.pricepaid, sales.commission, salesid order by salesid limit 10; salesid | pricepaid | commission | difference | to_char ---------+-----------+------------+------------+----------------- 1 | 728.00 | 109.20 | 618.80 | dcxix 2 | 76.00 | 11.40 | 64.60 | lxv 3 | 350.00 | 52.50 | 297.50 | ccxcviii 4 | 175.00 | 26.25 | 148.75 | cxlix 5 | 154.00 | 23.10 | 130.90 | cxxxi 6 | 394.00 | 59.10 | 334.90 | cccxxxv 7 | 788.00 | 118.20 | 669.80 | dclxx 8 | 197.00 | 29.55 | 167.45 | clxvii 9 | 591.00 | 88.65 | 502.35 | dii 10 | 65.00 | 9.75 | 55.25 | lv (10 rows)
以下示例将货币符号添加到to_char列中显示的差值中：
select salesid, pricepaid, commission, (pricepaid - commission) as difference, to_char(pricepaid - commission, 'l99999D99') from sales group by sales.pricepaid, sales.commission, salesid order by salesid limit 10; salesid | pricepaid | commission | difference | to_char --------+-----------+------------+------------+------------ 1 | 728.00 | 109.20 | 618.80 | $ 618.80 2 | 76.00 | 11.40 | 64.60 | $ 64.60 3 | 350.00 | 52.50 | 297.50 | $ 297.50 4 | 175.00 | 26.25 | 148.75 | $ 148.75 5 | 154.00 | 23.10 | 130.90 | $ 130.90 6 | 394.00 | 59.10 | 334.90 | $ 334.90 7 | 788.00 | 118.20 | 669.80 | $ 669.80 8 | 197.00 | 29.55 | 167.45 | $ 167.45 9 | 591.00 | 88.65 | 502.35 | $ 502.35 10 | 65.00 | 9.75 | 55.25 | $ 55.25 (10 rows)
以下示例列出了完成每次销售的世纪。
select salesid, saletime, to_char(saletime, 'cc') from sales order by salesid limit 10; salesid | saletime | to_char ---------+---------------------+--------- 1 | 2008-02-18 02:36:48 | 21 2 | 2008-06-06 05:00:16 | 21 3 | 2008-06-06 08:26:17 | 21 4 | 2008-06-09 08:38:52 | 21 5 | 2008-08-31 09:17:02 | 21 6 | 2008-07-16 11:59:24 | 21 7 | 2008-06-26 12:56:06 | 21 8 | 2008-07-10 02:12:36 | 21 9 | 2008-07-22 02:23:17 | 21 10 | 2008-08-06 02:51:55 | 21 (10 rows)
以下示例将 EVENT 表中的每个 STARTTIME 值转换为由小时、分钟、秒和时区组成的字符串：
select to_char(starttime, 'HH12:MI:SS TZ') from event where eventid between 1 and 5 order by eventid; to_char ---------- 02:30:00 UTC 08:00:00 UTC 02:30:00 UTC 02:30:00 UTC 07:00:00 UTC (5 rows) (10 rows)
以下示例显示了秒、毫秒和微秒的格式设置。
select sysdate, to_char(sysdate, 'HH24:MI:SS') as seconds, to_char(sysdate, 'HH24:MI:SS.MS') as milliseconds, to_char(sysdate, 'HH24:MI:SS:US') as microseconds; timestamp | seconds | milliseconds | microseconds --------------------+----------+--------------+---------------- 2015-04-10 18:45:09 | 18:45:09 | 18:45:09.325 | 18:45:09:325143
