starts_with
NAME
starts_with(): Checks whether given text starts with given prefix..TYPE
FunctionDESCRIPTION
A string p is a prefix of s if there is a string t such that CONCAT(p, t) = s.
SYNOPSIS
starts_with(txt TEXT CHARSET utf8, prefix TEXT CHARSET utf8) RETURNS INT UNSIGNED
Input:
- txt: an arbitrary text.
- prefix: the string suspected/expected to be a prefix as txt.
If txt does indeed start with prefix, starts_with returns the number of characters in the prefix. That is, the length of prefix.
In case of mismatch (not a prefix), the function returns 0.
One should note that a positive number holds in SQL as a TRUE value, whereas 0 holds as FALSE. Also note that in the particular case of the empty string being the prefix, the value 0 is always returned.
EXAMPLES
Trim text (spaces between literals are unaffected):
SELECT starts_with('The quick brown fox', 'The quick') as is_prefix;
+-----------+
| is_prefix |
+-----------+
| 9 |
+-----------+
Similar to the above, quoted for clarity:
SELECT starts_with('The quick brown fox', 'fox') as is_prefix;
+-----------+
| is_prefix |
+-----------+
| 0 |
+-----------+