| 函数名 | 含义及实例 |
| abs | abs(x) - returns the absolute value of x
Example:
> SELECT abs(0) FROM src LIMIT 1;
0
> SELECT abs(-5) FROM src LIMIT 1;
5 |
| acos | acos(x) - returns the arc cosine of x if -1<=x<=1 or NULL otherwise
Example:
> SELECT acos(1) FROM src LIMIT 1;
0
> SELECT acos(2) FROM src LIMIT 1; |
| add_months | add_months(start_date, num_months) - Returns the date that is num_months after start_date.
start_date is a string in the format 'yyyy-MM-dd HH:mm:ss' or 'yyyy-MM-dd'. num_months is a number. The time part of start_date is ignored.
Example:
> SELECT add_months('2009-08-31', 1) FROM src LIMIT 1;
'2009-09-30' |
| aes_decrypt | aes_decrypt(input binary, key string/binary) - Decrypt input using AES.
AES (Advanced Encryption Standard) algorithm. Key lengths of 128, 192 or 256 bits can be used. 192 and 256 bits keys can be used if Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files are installed. If either argument is NULL or the key length is not one of the permitted values, the return value is NULL.
Example: > SELECT aes_decrypt(unbase64('y6Ss+zCYObpCbgfWfyNWTw=='), '1234567890123456');
'ABC' |
| aes_encrypt | aes_encrypt(input string/binary, key string/binary) - Encrypt input using AES.
AES (Advanced Encryption Standard) algorithm. Key lengths of 128, 192 or 256 bits can be used. 192 and 256 bits keys can be used if Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files are installed. If either argument is NULL or the key length is not one of the permitted values, the return value is NULL.
Example: > SELECT base64(aes_encrypt('ABC', '1234567890123456'));
'y6Ss+zCYObpCbgfWfyNWTw==' |
| and | a1 and a2 and ... and an - Logical and |
| array | array(n0, n1...) - Creates an array with the given elements |
| array_contains | array_contains(array, value) - Returns TRUE if the array contains value.
Example:
> SELECT array_contains(array(1, 2, 3), 2) FROM src LIMIT 1;
true |
