CPTL_AST_NTE_TXT

SELECT
ast.CPTL_AST_SYS_ID,
ast.CPTL_AST_NTE_TXT,
LENGTH(ast.CPTL_AST_NTE_TXT) AS txt_length
FROM PUR_PO_CPTL_AST_SYS_T ast
WHERE
LENGTH(ast.CPTL_AST_NTE_TXT) > 255;