Collation sequences example

The examples below identify the collation sequences that would be used to determine the results of text comparisons that may be performed by various SQL statements. Note that a text comparison may not be required, and no collation sequence used, in the case of numeric, BLOB, or NULL values.

```CREATE TABLE t1(
x INTEGER PRIMARY KEY,
a,                 /* collating sequence BINARY */
b COLLATE BINARY,  /* collating sequence BINARY */
c COLLATE RTRIM,   /* collating sequence RTRIM  */
d COLLATE NOCASE   /* collating sequence NOCASE */
);

/* Text comparison a=b is performed using the BINARY sequence. */
SELECT x FROM t1 WHERE a = b ORDER BY x;
--result 1 2 3

/* Text comparison a=b is performed using the RTRIM sequence. */
SELECT x FROM t1 WHERE a = b COLLATE RTRIM ORDER BY x;
--result 1 2 3 4

/* Text comparison d=a is performed using the NOCASE sequence. */
SELECT x FROM t1 WHERE d = a ORDER BY x;
--result 1 2 3 4

/* Text comparison a=d is performed using the BINARY sequence. */
SELECT x FROM t1 WHERE a = d ORDER BY x;
--result 1 4

/* Text comparison 'abc'=c is performed using the RTRIM sequence. */
SELECT x FROM t1 WHERE 'abc' = c ORDER BY x;
--result 1 2 3

/* Text comparison c='abc' is performed using the RTRIM sequence. */
SELECT x FROM t1 WHERE c = 'abc' ORDER BY x;
--result 1 2 3

/* Grouping is performed using the NOCASE sequence (Values
** 'abc', 'ABC', and 'Abc' are placed in the same group). */
SELECT count(*) FROM t1 GROUP BY d ORDER BY 1;
--result 4

/* Grouping is performed using the BINARY sequence.  'abc' and
** 'ABC' and 'Abc' form different groups */
SELECT count(*) FROM t1 GROUP BY (d || '') ORDER BY 1;
--result 1 1 2

/* Sorting or column c is performed using the RTRIM sequence. */
SELECT x FROM t1 ORDER BY c, x;
--result 4 1 2 3

/* Sorting of (c||'') is performed using the BINARY sequence. */
SELECT x FROM t1 ORDER BY (c||''), x;
--result 4 2 3 1

/* Sorting of column c is performed using the NOCASE sequence. */
SELECT x FROM t1 ORDER BY c COLLATE NOCASE, x;
--result 2 4 3 1

```