# SQLCODE -420: String argument not acceptable to function Source: https://wndsoftware.com/mainframe-errors/sqlcode-420 ### SQLCODE -420: String argument not acceptable to function SQLCODE -420 (SQLSTATE 22018) means a character string passed to a function or a cast isn't in a form that function accepts, for example letters or blanks given to DECIMAL or INTEGER. The message names the function, or the target type of the cast. #### Other names for this code Also written as `SQL -420`, `SQLCODE=-420`, `SQLCODE = -420`, `db2 -420`, `sqlstate 22018`, `SQL0420N`, `db2 string argument not acceptable`, `SQL0420`, `sqlcode -420 decfloat`. ### What it means Some functions read a string and turn it into something else. DECIMAL, INTEGER and CAST to a numeric type need a string that follows the rules for an SQL number. When a string breaks those rules, Db2 fails the statement at run time with -420. The token in the message is the function name. For a cast it is the target data type. Since Db2 10 for z/OS, this code appears in places where it didn't before. When a character string is compared with a number, Db2 now casts the string to DECFLOAT(34), and the message then names DECFLOAT. Db2 10 in new-function mode also casts string input host variables to numeric targets. An empty or blank string sent from a client for a numeric column fails with -420 where older releases returned -301. Because the cast happens row by row, -420 depends on the data. A query can run cleanly for months and fail the day a bad value appears. A change of access path can also make it come and go, since Db2 may then evaluate the cast on rows it used to skip. ### Common causes - A character column holds values that aren't numbers, and the SQL compares it with a number, as in `WHERE ACCT_CODE = 1234`. One bad row in the rows Db2 examines is enough. - Blank or empty strings are converted to a number, either by an explicit CAST or by a client passing a blank for a numeric parameter. - Strings with thousands separators, currency signs or other formatting, such as `'1,234.50'`, are passed to DECIMAL or a numeric cast. - The system uses DECIMAL=COMMA in DSNHDECP, so a comma is the decimal separator and strings written with a period don't convert as expected. IBM fixed one Db2 10 problem in this area under APAR PM70908. - Generated SQL quotes numbers in a form Db2 won't parse, for example with spaces in the wrong place. APAR PH31035 fixed a case of this in the Db2 Administration Tool. ### How to find the problem - Take the function or type name from the message. DECFLOAT usually means an implicit cast from a comparison between a string and a number. - Find the string expressions in the statement that feed that function or comparison. - Look for bad values, for example `SELECT ACCT_CODE FROM ... WHERE TRANSLATE(ACCT_CODE, ' ', '0123456789') <> ' ' OR ACCT_CODE = ' '`, which lists values with characters other than digits, and blank values. - For client programs, trace the parameter values sent. IBM points to IFCID 0366 trace records to find the inputs affected by the Db2 10 implicit cast change. ### How to fix it - Compare like with like. If ACCT_CODE is a CHAR column, write `WHERE ACCT_CODE = '1234'` so no cast is needed. - Clean the bad values at the source, and validate numeric input before it reaches Db2. - Guard the conversion with a CASE expression that only casts values made of digits. - Fix the client so it sends a null or a real number instead of a blank string. - Apply the PTFs for known APARs if the failing SQL comes from IBM code. The DDF_COMPATIBILITY setting DISABLE_IMPCAST_NJV can turn off implicit casting for older non-Java drivers, but IBM marks it deprecated, so treat it as a short-term workaround. ### What it looks like ```text DSNT408I SQLCODE = -420, ERROR: THE VALUE OF A STRING ARGUMENT WAS NOT ACCEPTABLE TO THE DECIMAL FUNCTION DSNT418I SQLSTATE = 22018 SQLSTATE RETURN CODE DSNT415I SQLERRP = DSNXRDEC SQL PROCEDURE DETECTING ERROR ``` ### IBM documentation [IBM documentation: -420](https://www.ibm.com/docs/en/db2-for-zos/13.0.0?topic=codes-420). Use the documentation for your installed release. [Report a correction to WND Software](https://wndsoftware.com/contact#message). Technical reviewer: [Albert Joseph](https://wndsoftware.com/authors/albert-joseph), WND Software. Last reviewed 2026-10-18 by the WND Software team. Written in our own words. For the full reference, check IBM’s Db2 for z/OS documentation for your release. ### Related codes [SQLCODE -401 Operands not comparable Read →](https://wndsoftware.com/mainframe-errors/sqlcode-401) [SQLCODE -180 Invalid date, time or timestamp string Read →](https://wndsoftware.com/mainframe-errors/sqlcode-180) [SQLCODE -301 Input host variable type can't be used Read →](https://wndsoftware.com/mainframe-errors/sqlcode-301) [SQLCODE -302 Input value invalid or too large Read →](https://wndsoftware.com/mainframe-errors/sqlcode-302) [SQLCODE -413 Overflow during numeric conversion Read →](https://wndsoftware.com/mainframe-errors/sqlcode-413) ### Questions #### Why does the message say DECFLOAT when I never used it? Db2 casts a string to DECFLOAT(34) when you compare it with a number. The message names DECFLOAT because that is the cast that failed. #### Why did -420 start after we moved to Db2 10? Db2 10 new-function mode casts strings to numbers implicitly. Comparisons and inputs that used to fail with -401 or -301 now get cast, and a bad string fails at run time with -420. #### What do Db2 for LUW and IBM i report? Db2 for LUW reports SQL0420N, invalid character found in a character string argument, and IBM i reports SQL0420. Both use SQLSTATE 22018. [Db2 SQLCODEs](https://wndsoftware.com/mainframe-errors/db2-sqlcodes) · [SQLCODE -413](https://wndsoftware.com/mainframe-errors/sqlcode-413) · [SQLCODE -421](https://wndsoftware.com/mainframe-errors/sqlcode-421) [← All error codes](https://wndsoftware.com/mainframe-errors/)