---
name: "PQparamExec"
section: "3"
platform: "linux"
package: "libpqtypes-dev"
version: "1.5.1-9"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/PQparamExec"
---

# PQparamExec(3)

Executes a paramertized query using the parameters in a PGparam.

## NAME

PQparamExec, PQparamExecPrepared - Executes a paramertized query using the parameters in a PGparam.

## SYNOPSIS

**#include \<libpqtypes.h\>**\

**PGresult \*PQparamExec(PGconn \****conn***, PGparam \****param***,**\
\
                       **const char \****command***, int** *resultFormat***);**\
 **PGresult \*PQparamExecPrepared(PGconn \****conn***, PGparam \****param***,**\
\
                               **const char \****stmtName***, int** *resultFormat***);**

## DESCRIPTION

*The PQparamExec() and PQparamExecPrepared() functions execute* *a parameterized query using the parameters in a PGparam.  The only difference* *between these functions is that PQparamExec() expects a parameterized* *command string while PQparamExecPrepared() expects a stmtName* *previously prepared via PQprepare().*

*Both functions take a param argument, which must contain the same number* *of parameters as either the command string or previously prepared stmtName.* *Internally, the param is transformed into parallel arrays that are* *supplied to a PQexecParams() or PQexecPrepared() call.*

*The resultFormat argument indicates if text or binary results are desired;* *a value of zero or one respectively.  PQgetf supports both text and binary* *result formats, with the exclusion of arrays and composites which only support binary.*

## RETURN VALUE

*On success, a pointer to a PGresult is returned.  On error, NULL is* *returned and [PQgeterror(3)](/PQgeterror/3.md) will contain an error message.*

**IMPORTANT!**\
 *There is a difference in behavior between PQparamExec() and PQparamExecPrepared()* *and the libpq functions they wrap, PQexecParams() and PQexecPrepared().* *PQparamExec() and PQparamExecPrepared() only return a non-NULL* *PGresult when the result status is either PGRES\_COMMAND\_OK, PGRES\_TUPLES\_OK or* *PGRES\_EMPTY\_QUERY.  If these functions detect any other result status, the* *PGresult is cleared and a NULL result is returned.  Before clearing the PGresult* *and returning NULL, these functions first copy the result error message into the* *libpqtypes error system, accessible via [PQgeterror(3)](/PQgeterror/3.md).  This allows applications* *to get a result´s error message without needing the result object.  conn error* *messages are also copied to the libpqtypes error system.*

*This behavior difference provides a single error indicator, a NULL return, and a* *single function that can get the error message, PQgeterror().*

## EXAMPLES

### Using PQparamExec

*The example uses PQparamExec() to execute a query using a PGparam.* *The example also demonstrates how to detect a failed exec and output an error* *message.*

```

```

**PGparam \*param = PQparamCreate(conn);**

**if(!PQputf(param, "%text %int4", "ACTIVE", CAT\_CAR))** **{**\
 	**fprintf(stderr, "PQputf: %s\\n", PQgeterror());** **}** **else** **{**\
 	**PGresult \*res = PQparamExec(conn, param,**\
 		**"SELECT \* FROM t WHERE status=$1 AND category=$2", 1);**

	**if(!res)**\
 		**fprintf(stderr, "PQparamExec: %s\\n", PQgeterror());**\
 	**else**\
 		**print\_results(res);**

	**PQclear(res);** **}**

**PQparamClear(param);**

### Using PQparamExecPrepared

*PQparamExecPrepared() is behaves identically to PQparamExec(), except* *PQparamExecPrepared() requires that a statement has been previously prepared* *via PQprepare().  Also, a stmtName is supplied rather than a parameterized* *command string.*

## AUTHOR

*A contribution of eSilo, LLC. for the PostgreSQL Database Management System.* *Written by Andrew Chernow and Merlin Moncure.*

## REPORTING BUGS

*Report bugs to \<libpqtypes@esilo.com\>.*

## COPYRIGHT

*Copyright (c) 2011 eSilo, LLC. All rights reserved.*\
 *This is free software; see the source for copying conditions.* *There is NO warranty; not even for MERCHANTABILITY or  FITNESS* *FOR A PARTICULAR PURPOSE.*

## SEE ALSO

*[PQparamCreate(3)](/PQparamCreate/3.md), [PQparamSendQuery(3)](/PQparamSendQuery/3.md), [PQparamSendQueryPrepared(3)](/PQparamSendQueryPrepared/3.md)*