| SQL adaptation guide For Sybase ASE 15.5+ / Data manipulation | |
Informix® SQL statements can use subscripts on columns defined with the character data type:
SELECT ... FROM tab1 WHERE col1[2,3] = 'RO'
SELECT ... FROM tab1 WHERE col1[10] = 'R' -- Same as col1[10,10]
UPDATE tab1 SET col1[2,3] = 'RO' WHERE ...
SELECT ... FROM tab1 ORDER BY col1[1,3]
While Sybase ASE provides the SUBSTR() function, to extract a substring from a string expression:
SELECT .... FROM tab1 WHERE SUBSTRING(col1,2,2) = 'RO'
SELECT SUBSTRING('Some text',6,3 ) FROM DUAL -- Gives 'tex'
You must replace all Informix col[x,y] expressions by SUBSTRING(col,x,y-x+1).
In UPDATE instructions, setting column values through subscripts will produce an error with Sybase ASE:
UPDATE tab1 SET col1[2,3] = 'RO' WHERE ...
is converted to:
UPDATE tab1 SET SUBSTRING(col1,2,3-2+1) = 'RO' WHERE ...
Column subscripts in ORDER BY expressions are also converted and produce an error with Sybase ASE:
SELECT ... FROM tab1 ORDER BY col1[1,3]
is converted to:
SELECT ... FROM tab1 ORDER BY SUBSTRING(col1,1,3-1+1)