DEF[INE] [variable]|[variable = text] 1. 2. 3. 定义一个用户变量并且可以分配给它一个CHAR值。 assign the value MANAGER to the variable POS, type: SQL> DEFINE POS = MANAGER assign the CHAR value 20 to the variable DEPTNO, type: SQL> DEFINE DEPTNO = 20 list the definition of DEPTNO,...
variable_name data_type [DEFAULT value]; BEGIN -- Statements using the variable END $$; Example 1: Declaring and Using a Variable Code: -- Use an anonymous DO block to declare a variable DO $$ DECLARE employee_count INTEGER; -- Declare an integer variable BEGIN -- Assign a value to t...
-- Build SQL statement to support bind variables. sql_statement VARCHAR2(4000 CHAR) := 'UPDATE THE (SELECT street_address ' || ' FROM addresses ' || ' WHERE address_id = 21) ' || 'SET column_value = :1 ' || 'WHERE column_value = :2'; BEGIN -- Use dynamic SQL to run the...
variable->varno) {case INNER_VAR:/* get the tuple from the inner node */ scratch.opcode = EEOP_ASSIGN_INNER_VAR;break;case OUTER_VAR:/* get the tuple from the outer node */ scratch.opcode = EEOP_ASSIGN_OUTER_VAR;break;/* INDEX_VAR is handled by default case */default:/*...
To assign environment variables (e.g., CC, CFLAGS...), specify them as VAR=VALUE. See belowfordescriptions of some of the useful variables. Defaultsforthe options are specifiedinbrackets. Configuration:-h, --help display this help and exit--help=shortdisplay options specific to this package...
* use ASSIGN_*_VAR. Instead let the normal expression * machinery handle it (which'll possibly error out). */ if (!attr->attisdropped && variable->vartype == attr->atttypid) { isSafeVar = true; } } /* 对于简单的情况只需要 EEOP_ASSIGN_*_VAR 即可 */ ...
(as determined on startup) */enumtrivaluegetPassword;/* prompt the user for a username and password */FILE *cur_cmd_source;/* describe the status of the current main loop */boolcur_cmd_interactive;intsversion;/* backend server version */constchar*progname;/* in case you renamed psql *...
/* * Free any old value, in case re-entering block, and * initialize to NULL */ assign_simple_var(estate, var, (Datum) 0, true, false); if (var->default_val == NULL) { /* * If needed, give the datatype a chance to reject * NULLs, by assigning a NULL to the variable. ...
-“CONSTANT” is an optional parameter, used to assign a non-changeable value to the given variable. - Replace the “data_type” with a valid data type, such as INT, DATE, TEXT, etc. - The “NOT NULL” is an optional parameter that makes sure that the variable must contain a non-...
Previously, the string value of such variables was set to match the variable name during cursor assignment; now it will be assigned during OPEN, and will not match the variable name. To restore the previous behavior, assign the desired portal name to the cursor variable before OPEN. PG16 cre...