On Mon, Nov 10, 2014 at 4:40 AM, Prakash Premkumar <[email protected]>
wrote:
> The where clause in sqlite is encoded as a tree
>
> Let's say I have select statement like :
>
> SELECT * from employee where salary = 3+5*4+3;
>
> The tree which takes care of operator precedence is :
>
> =
> / \
> salary +
> / \
> 3 3
> /
> *
> / \
> 5 4
>
No.
If you recompile the SQLite command-line shell (sqlite3.exe) using the
-DSQLITE_ENABLE_SELECTTRACE option, then you can enter:
CREATE TABLE employee(employee_id,salary);
.selecttrace 0x100
SELECT * FROM employee WHERE salary = 3+5*4+3;
The ".selecttrace 0x100" line will cause SQLite to print out its parse tree
using ascii-art. The result:
'-- SELECT
|-- result-set
| '-- op=116
|-- FROM
| '-- {-1,*} employee
'-- WHERE
'-- EQ
|-- ID 'salary'
'-- ADD
|-- ADD
| |-- 3
| '-- MUL
| |-- 5
| '-- 4
'-- 3
--
D. Richard Hipp
[email protected]
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