SQL frontend

golars.sql exposes a subset SQL frontend that compiles into the same lazy plan as the Go API. Run queries from the shell, from the REPL, or programmatically.

From the CLI

golars sql "SELECT dept, SUM(amount) AS total FROM sales GROUP BY dept ORDER BY total DESC" sales.csv

Each file becomes a table whose name is the filename stem. Multiple files register as separate tables so cross-file queries Just Work:

golars sql "SELECT t.*, s.name FROM trades t" trades.csv symbols.csv

From Go

import "github.com/Gaurav-Gosain/golars/sql"

session := sql.NewSession()
defer session.Close()
session.Register("people", df)

out, err := session.Query(ctx, "SELECT name FROM people WHERE age > 25")
defer out.Release()

Grammar

SELECT [DISTINCT] projection_list
FROM table_name
[WHERE predicate]
[GROUP BY col_list]
[ORDER BY col_list [ASC|DESC]]
[LIMIT n]

projection_list:

• *
• col[, col...] (optionally each with AS name)
• agg(col)[, ...] (agg: SUM, MIN, MAX, AVG, MEAN, COUNT, FIRST, LAST)
• any mix of the above when there is a GROUP BY

predicate:

• col OP value [AND|OR col OP value]...
• OP is one of =, !=, <, <=, >, >=

value:

• integer literal (42)
• float literal (3.14)
• single-quoted or double-quoted string ('us', "ops")
• true, false

Limitations

• No JOIN clause yet (use the df.Join(...) API directly).
• No window functions (use Expr.Over(keys...) in Go).
• No subqueries.
• No arithmetic in SELECT expressions (use WithColumns in Go).

All of these come free with golars' Go API; the SQL frontend focuses on what ad-hoc shell queries need.

From the MCP server

golars-mcp exposes the same SQL compiler as a tool named sql. Host LLMs invoke it with {query, files} arguments. See MCP integration.