Difference between revisions of "KEYLOOKUP()"
Yvonne.milne (Talk | contribs) (Created page with "==Purpose== Function to perform a cross-table lookup ==Syntax== KEYLOOKUP(<workarea | alias>, <"tagname">, <key expression>, <valueExpr>) ==See Also== LOOKUP(), [[RLOOKU...") |
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==Description== | ==Description== | ||
The KEYLOOKUP() function looks up the specified index <key expression> in the index <tagname> of the specified <workarea | alias>. The KEYLOOKUP() function then evaluates the expression <valueExpr>, and returns the value of the <valueExpr> if the <key expression> is found. The KEYLOOKUP() function returns a null string if the <key expression> is not found. | The KEYLOOKUP() function looks up the specified index <key expression> in the index <tagname> of the specified <workarea | alias>. The KEYLOOKUP() function then evaluates the expression <valueExpr>, and returns the value of the <valueExpr> if the <key expression> is found. The KEYLOOKUP() function returns a null string if the <key expression> is not found. | ||
| + | |||
| + | The current record position in the specified <workarea | alias> cursor is not moved so this function can also safely be used in SQL queries. If the specified <alias> is not already open then Lianja will open the table automatically. | ||
==Example== | ==Example== | ||
<code lang="recital"> | <code lang="recital"> | ||
open database southwind | open database southwind | ||
| − | use | + | use orders in 0 |
| − | + | ? keylookup("employees","employeeid",orders.employeeid, employees.lastname) | |
| − | ? keylookup(employees,"employeeid",orders.employeeid, employees.lastname) | + | |
</code> | </code> | ||
Revision as of 12:13, 7 December 2012
Contents
Purpose
Function to perform a cross-table lookup
Syntax
KEYLOOKUP(<workarea | alias>, <"tagname">, <key expression>, <valueExpr>)
See Also
LOOKUP(), RLOOKUP(), SEEK(), SET RELATION
Description
The KEYLOOKUP() function looks up the specified index <key expression> in the index <tagname> of the specified <workarea | alias>. The KEYLOOKUP() function then evaluates the expression <valueExpr>, and returns the value of the <valueExpr> if the <key expression> is found. The KEYLOOKUP() function returns a null string if the <key expression> is not found.
The current record position in the specified <workarea | alias> cursor is not moved so this function can also safely be used in SQL queries. If the specified <alias> is not already open then Lianja will open the table automatically.
Example
open database southwind use orders in 0 ? keylookup("employees","employeeid",orders.employeeid, employees.lastname)
