Firebird 2.1 Language Reference Update

Internal functions
overlay ('Goodbye' placing '' from 4 for 3) -- returns 'Gooe'
overlay ('Goodbye' placing '' from 4 for 20) -- returns 'Goo'
overlay ('' placing 'Hello' from 4) -- returns 'Hello'
overlay ('' placing 'Hello' from 4 for 0) -- returns 'Hello'
overlay ('' placing 'Hello' from 4 for 20) -- returns 'Hello'
Warning
When used on a BLOB, this function may need to load the entire object into memory. This may affect performance
if huge BLOBs are involved.
See also: REPLACE()
Available in: DSQL, PSQL
Added in: 2.1
PI()
Description: Returns an approximation of the value of #.
Result type: DOUBLE PRECISION
Syntax:
PI ()
Important
If the external function PI is declared in your database, it will override the internal function. To make the
internal function available, DROP or ALTER the external function (UDF).
Available in: DSQL, PSQL
Added in: 2.1
POSITION()
Description: Returns the (1-based) position of the first occurrence of a substring in a host string. With the
optional third argument, the search starts at a given offset, disregarding any matches that may occur earlier in
the string. If no match is found, the result is 0.
Result type: INTEGER
Syntax:
POSITION ()
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